Link: FreePBX: Inbound number not working help [might also be useful for other SIP-based PBX administrators]

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

This may be of some help to those of you still using “that” software, that are having problems getting a new DID (inbound number) to work.  Note this tip might be equally useful for all Asterisk users, or even for administrators of other SIP-based PBX software.

FreePBX: Inbound number not working help (sysadminnet)

Related article

Link to POSSIBLE method of porting a landline phone number to Google Voice for free (well, except for the $20 that Google Voice charges)

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

Google Voice will only allow you to port cell phone numbers to their service (don’t ask ME why — seems stupid, but that’s their rule) so if you want to port a landline number, you first have to temporarily port it to a cell phone provider, then from there port it to Google Voice. Most of the published methods that I have seen for doing this involve paying out some small sum (usually around $20) to get a “disposable” cell phone (so after adding the $20 that Google Voice changes to do the port you are out almost $40), however I just stumbled across a thread that suggests it may be possible to do it for free, IF you have (or can borrow) an old Verizon or Page Plus cell phone that’s not currently being used.  Note this may not work in all areas (there are still areas of the country where Google Voice can’t port numbers) and I don’t guarantee it in any case because I haven’t personally tried it, but if you’ve been thinking of porting your landline number to Google Voice, this MIGHT save you a few bucks:

Post on DansDeals.com Forums

Again, although it’s not clear from this thread, Google Voice will still charge you $20 to do the port, but if you can get this to work it could save you some money.  Note that if you are served by some Podunk (independent) telephone company there’s a good chance it won’t work, so keep that in mind if losing your number would be a major catastrophe for you.

Logitech C910 Webcam (Logitech Webcam Software) crashing on Mac OS X 10.7

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

This falls into the category of “notes I am posting for myself so I don’t lose them”.  A Logitech C910 Webcam works under Mac OS X (more or less — some users have had more success than others), but the Logitech Webcam Software is buggy and Logitech seems to be in no big hurry to fix it, as can be attested to by the many posts in their Webcams forum complaining about problems using the device with a Mac.  I followed all the instructions in this thread (which was actually for OS X 10.6 but I was grasping at straws) but nothing helped – after I uninstalled and reinstalled the Webcam software, it would run fine ONCE and then after that, every time I’d try to run it again, it would crash immediately after opening.  This was not always the case, but perhaps something was broken during an upgrade.

I figured out that if I go into /Users/username/Library/Preferences/ and remove the files com.logishrd.LWS.plist and com.logishrd.LWS.plist.lockfile it would then not crash on the next run attempt.  So, Logitech’s software is buggy because the mere presence of these files should not cause the software to crash.  Note this is with the lws220.dmg software so if they ever release a newer version it just might fix the problem.

I suppose you could write an AppleScript to delete the two offending files and then launch the Logitech Webcam Software, but I have not got around to that yet (I An Not A Programmer).  My question is, why doesn’t Logitech fix their damn software instead of leaving OS X users hanging, waiting for a solution? People have been complaining about these issues for at least a year and a half now!

Review of FreeSWITCH Cookbook by Anthony Minessale, Michael S Collins, Darren Schreiber, Raymond Chandler (Packt Publishing)

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog. In order to comply with Federal Trade Commission regulations, I am disclosing that he received a free product sample of the item under review prior to writing the review, and that any links to Amazon.com in this article are affiliate links, and if you make a purchase through one of those links I will receive a small commission on the sale.

The FreeSWITCH Cookbook is the second book from Packt Publishing on the subject of FreeSWITCH, which in my opinion may someday soon be the “telephony software engine” that replaces Asterisk in popularity. I’ve previously reviewed the earlier book, FreeSWITCH 1.0.6, and this book builds on that one. If you know nothing at all about FreeSWITCH, you’ll probably want to start with the earlier book, because it gives you all the basics.  The publisher was kind enough to send me a complementary copy of the new book for review purposes.

This book, as the name implies, is a “cookbook” in that it gives “recipes” for how to do certain tasks. Just as an actual cookbook presupposes certain knowledge (that you know how to operate an oven; the difference between certain measuring units, etc.) this book tends to start with the assumption that you already have a grasp of how to set up FreeSWITCH, but you may need examples of the configuration necessary to perform certain tasks. And, that’s what this book gives you. The idea, I think, is that if even one of the “recipes” saves you a couple of hours of head-scratching and trying to figure out how to do something, then that justifies the cost of the book.

Normally in this type of review I would list the chapters, but in the case of this book you’ll probably want to know what’s in each chapter. So, here is the complete Table of Contents from the Packt Publishing web site:

  • Preface
  • Chapter 1: Routing Calls
    • Introduction
    • Internal calls
    • Incoming DID calls
    • Outgoing calls
    • Ringing multiple endpoints simultaneously
    • Ringing multiple endpoints sequentially (simple failover)
    • Advanced multiple endpoint calling with enterprise originate
    • Time of day routing
    • Manipulating To: headers on registered endpoints to reflect DID numbers
  • Chapter 2: Connecting Telephones and Service Providers
    • Introduction
    • Configuring a SIP phone to register with FreeSWITCH
    • Connecting audio devices with PortAudio
    • Using FreeSWITCH as a softphone
    • Configuring a SIP gateway
    • Configuring Google Voice
    • Codec configuration
  • Chapter 3: Processing Call Detail Records (available as a sample chapter in PDF format)
    • Introduction
    • Using CSV CDRs
    • Using XML CDRs
    • Inserting CDRs into a backend database
    • Using a web server to handle XML CDRs
    • Using the event socket to handle CDRs
  • Chapter 4: External Control
    • Introduction
    • Getting familiar with the fs_cli interface
    • Setting up the event socket library
    • Establishing an inbound event socket connection
    • Establishing an outbound event socket connection
    • Using fs_ivrd to manage outbound connections
    • Filtering events
    • Launching a call with an inbound event socket connection
    • Using the ESL connection object for call control
    • Using the built-in web interface
  • Chapter 5: PBX Functionality
    • Introduction
    • Creating users
    • Accessing voicemail
    • Company directory
    • Using phrase macros to build sound prompts
    • Creating XML IVR menus
    • Music on hold
    • Creating conferences
    • Sending faxes
    • Receiving faxes
    • Basic text-to-speech with mod_flite
    • Advanced text-to-speech with mod_tts_commandline
    • Listening to live calls with telecast
    • Recording calls
  • Index

As you can see, the order progresses from the basics (setting up your extensions, and inbound and outbound routing) to the sort of things you might want to do in a more full-featured PBX. Chapter 4 in particular will be of interest to many developers. I’ll quote from the introduction to that chapter:

One of the most powerful features of FreeSWITCH is the ability to connect to it and control it from an external resource. This is made possible by the powerful FreeSWITCH event system and its connection to the outside world: the event socket. The event socket interface is a simple TCP-based connection that programmers can use to connect to the inner-workings of a FreeSWITCH server. Furthermore, the FreeSWITCH developers have also created the Event Socket Library (ESL), which is an abstraction layer to make programming with the event socket a lot simpler. The following languages are supported by ESL:

  • C/C++
  • Lua
  • Perl
  • PHP
  • Python
  • Ruby
  • TCL

Keep in mind that the ESL is only an abstraction library—you can connect to the event socket with any socket-capable application, including telnet!

The tips in this chapter will focus most of their attention on using the event socket for some common use cases. The last tip, though, will introduce a particularly interesting way to connect to FreeSWITCH externally without using the event socket, namely, using the built-in web server that is enabled when you install mod_xml_rpc. Regardless of how you wish to control FreeSWITCH, it is highly recommended that you read the first recipe in this chapter, Getting familiar with the fs_cli interface, as this will serve you well in all aspects of working with FreeSWITCH.

This, of course, is somewhat analogous to controlling Asterisk via Asterisk Gateway Interface programming, but it appears that you get more functionality in FreeSWITCH, and more languages are supported.

I have said on many occasions that I am not a programmer, so in one sense I’m not exactly the target audience for this book.  However, I know just enough about coding to be able to appreciate when a book lays out examples in a clear, easy-to-understand manner, with enough comments for you to “get” what the author is trying to explain to you.  Personally, if I could just get over my hurdle of not fully grasping XML (which is actually strange, because I have no problem understanding basic HTML, which is very similar), I think that this book would be a lot more useful to me in understanding how to do things in FreeSWITCH.  I sort of “get” Asterisk dialplans a little bit, but for some odd reason XML is not nearly as understandable to me.  I guess everyone’s mind works a little differently.  If you work with FreeSWITCH and you don’t share my mental block with regard to XML, you are really going to like this book.  In terms of layout and readability, I think it’s one of the best titles I’ve seen from Packt.

One thing in particular I like about this book is that they don’t just give you the XML dialplan (although the XML is included), but the authors then explain to you how it works.  In addition, in many cases they also give you additional related information, such as tweaks you can make to the XML to perform slightly different functions or otherwise modify the behavior, and links to additional resources you made need.  So, you are not just viewing XML samples and then left on your own to puzzle out how they work!

In fact, I really only have one criticism of the book — it’s too short!  It’s only 134 pages from opening material to the index at the end.  But I’ll balance that by saying this — I’ve seen too many books that have a high page count, but a high percentage of the book is “filler”, much like the low-grade ground beef you buy at some supermarkets.  With this book, other than a few obligatory opening pages that tell you a bit about the authors and others involved with the book, it’s solid content.  No history of something or other, no long personal ramblings by the authors, etc. — just the “recipes” for doing the various things you might want to do in FreeSWITCH, and then the explanations as to how they work and other useful and relevant content.  You have to ask yourself the question, “Will this book save me time?” (almost certainly, if you are doing any of the things covered in the chapters of this book) and “How much is my time worth?”, and “Can I learn something from this book that would be useful to me?” (if you developing a project using FreeSWITCH, I can’t imagine how you wouldn’t).

My personal hope is that those who write, or who may be considering writing the next generation of GUI configuration programs for FreeSWITCH will get this book.  It basically shows you how to do everything you need to do to create a working PBX, and for those that are programmers, Chapter 4 is where the real magic is revealed.  That said, I would highly recommend this book for anyone attempting to develop a project using FreeSWITCH!

You can read a sample chapter here (PDF format).

FreeSWITCH Cookbook by Anthony Minessale, Michael S Collins, Darren Schreiber, Raymond Chandler (Amazon affiliate link)

Addendum: Just a bit more from the publisher’s site:

What you will learn from this book

  • Configure users and phones as well as connections to VoIP providers and even Google Voice
  • Control FreeSWITCH remotely with the powerful event socket interface
  • Route inbound and outbound calls
  • Handle call detail records, which includes inserting CDRs into a database
  • Enable text-to-speech conversion in your voice applications
  • Monitor calls via the FreeSWITCH Web interface

Don’t like the new "Unity" users interface in Ubuntu? Try this…

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.
Unity 2D from Ubuntu 11.04
Unity 2D from Ubuntu 11.04 (Photo credit: Wikipedia)

If you hate the Unity interface in the latest version of Ubuntu, try this.  From a terminal prompt, enter:

sudo apt-get install gnome-session-fallback

I’d assume that you could also install gnome-session-fallback from Synaptic if you prefer.  Then, choose “GNOME Classic” at signon.

Credit for this hint goes to this article:

I hate Ubuntu, but my mother-in-law loves it (ZDNet)

EDIT: For another approach that might be more pleasing to some users, see How to install Linux Mint’s Cinnamon Desktop on Ubuntu (Linux Stall)

PHP Bug can cause FreePBX Inbound Routes and Asterisk Phonebook entries to not work as expected

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

It appears there is a nasty bug in certain versions of PHP (almost certainly in version 5.3.3, and perhaps other versions as well) that can cause SOME inbound and outbound routes in FreePBX to be ignored.  Add this to the list of difficulties to plague some FreePBX users, but for once it’s not something the FreePBX developers did.

The symptom appears to be that you have an inbound route with a DID that starts with the number “2”, or an Asterisk Phonebook entry that starts with a “2”, but it doesn’t work as expected or gets changed to a negative number.  Not all patterns starting with “2” appear to be affected, but ten digit numbers in certain area codes (such as 248 here in Michigan) definitely are.  In the case of inbound routes, it appears that the numbers get stored in the MySQL database correctly, but when they get written out to extensions_additional.conf (the dialplan file that F—PBX generates for Asterisk to use) they get transformed into negative numbers.  Therefore, when a call comes in on that DID, Asterisk doesn’t recognize it and the call gets dropped (or if you accept calls for any DID then it’s handled as such a call, but a warning message is posted to the CLI and the log file).

For a discussion of this issue, see these threads in the PBX in a Flash forum:

Inbound DID routing (only catchall works)
(240) area code in Asterisk Phonebook

Just wanted to alert you to this in case you happen to have the buggy PHP version and things just aren’t working as they should be. The best fix is probably to upgrade PHP to a later version but that can cause other issues, or you may encounter unmet dependencies when trying to upgrade (in fact, if you come across a foolproof way to upgrade PHP on Centos, please let us know). If you are using PBX in a Flash, they’re aware of the issue and one would hope they’ll have a fix real soon now. If you are using any other FreePBX-based distro then you will have to bug the distributors of that distro for a fix. If you rolled your own, then good luck to you in upgrading PHP!

How to find the right spot to place a satellite dish

 

Important
This is an edited version of a post (actually two posts combined) that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.
Really stupid way to install a satellite dish

Quite some time back, I had read an article on The Consumerist site (“DirecTV Contractor: No, We Won’t Fix Our Botched Installation“) and in particular, the comments left by readers of the article, several of which come to the same conclusion that I came to a long time ago: There is no way any installer is going to care about your home the way you do. They don’t have to live in your home for many years, but you do. They don’t have to put up with a crappy looking install, or leaks or water damage to your home, or insects or rodents finding a new route up from your crawl space or basement – you do.

Nowadays you have broadband, cable and satellite installers that just don’t seem to care. In some cases the results can be tragic, in other cases just costly and/or inconvenient. It’s as though some companies just hire anyone, give them minimal training, and don’t even think to instruct them in basic courtesy. If I ran one of these companies, I’d hang signs in employee areas saying things like, “Please respect your customer – treat their home as if you had to live there for the next quarter century” (but then again, that may not work if you have an installer that couldn’t care less about his own home).

One thing that constantly amazes me about satellite installs is that installers put the dish on the roof. In any place that gets snow, that is an absolutely idiotic thing to do. Let me say this again: If the installation company wants to mount a satellite dish on your roof, they are a bunch of idiots (with one exception)! Now why would I say that? Because, unlike terrestrial television signals, you do NOT get any appreciable signal gain by mounting a satellite dish high off the ground. I have seen satellite dishes mounted at ground level that work just fine, at least until they get a pile of snow in front of them. There is only one good reason to mount a dish on a roof, and that’s where you need the additional height to get a clear signal over the top of trees in a neighbor’s yard (in which case you may simply be buying time until the trees get larger), or to clear some other obstruction such as an adjacent tall building. It’s very rare that the additional height actually makes a difference, but it’s not totally unheard of, particularly when a neighbor’s trees are involved.

At the very least, dishes should be mounted under the eaves in a location where snow or ice will not slide down the roof onto them, if such a location is available. For a great many people, perhaps even a majority, the ideal mounting option for a satellite dish is on a metal pole stuck into the ground, a few feet away from the side of the house (or further away if necessary to get a clear signal), where the dish is about five to six feet above ground level. This is high enough that the signal won’t be interrupted by people or animals walking nearby, but low enough that should snow accumulate in the dish, it can be easily brushed off with a broom. Who wants to climb up onto a roof to brush snow off of a dish?

But installers hate putting a dish on a metal pole because they have to make two trips: The first is to dig the hole, insert the metal pole, insert a piece of plastic pipe or tubing so you can run the cable out through the concrete and keep it underground (to avoid damage from lawn mowers, etc.), mix and pour three or four bags of concrete, level the metal pole in the concrete, and then keep the pole perfectly level while the concrete sets. You may note that I keep saying metal pole. You can buy a 10 foot long galvanized steel pipe at most home improvement stores that works great for the purpose. But some homeowners have tried using a treated wood pole – that’s a big mistake, because even though the pole won’t rot, it will warp and twist, and soon your signal disappears. On the second trip (after the concrete dries), the installer then has to install and aim the dish. Obviously it’s a lot faster and easier to just attach the dish to the roof or the eaves, and get it all done in one trip, and what do they care if it causes a leak or rots the wood?

Now you may be thinking that this is a reason to just get cable, but cable installers aren’t much better. They may not drill holes in your roof, but when drilling down through the floor they tend to drill holes four to six inches away from the wall instead of right next to it, and often they have no idea what’s below where they are drilling. It’s not uncommon for them to take out telephone wiring or (more rarely) electrical wiring, or to hit a water or sewer pipe with their drills. And they sure don’t seem to care about appearance sometimes – it’s not as though they make any effort to conceal that big, black wire, even when they could easily do so. As an example, drive around any manufactured housing development (a.k.a. mobile home park) and you will see cable wires running along the side of the home, when there is no reason those wires could not have gone through the floor and underneath the home – except that the installer would have had to pop off a couple pieces of skirting and used some fish tape to do it right.

The moral of this story is, if you value your home and you are the least bit handy, do your own installations. If necessary, have the dish installation company come out and show you the best location for a dish in your yard, and have them leave the dish with you. Buy the pole and the concrete and set the pole yourself (be sure to keep it level!). If you don’t feel you are handy enough to do this, then shadow the installer and if he is about to do anything you don’t like, stop him! You can try to keep it friendly (suggestion: try to get him to tell you stories about the poor installations he’s encountered on his job that have been done by other installers; that may have the effect of encouraging him to do better than they did) but in the end, remember that you will be living in the home and if he causes roof leaks, or leaves holes where the elements can penetrate or insects or rodents can enter, you will be living with the result – and you may not find the damage until the statue of limitations is long past, so you’ll be the one that has to pay for the repairs. If you rent, the landlord may take the damage off of your security deposit (particularly if you never gave prior notification that the install was taking place).

As an aside, I just love the television commercials where the cable companies try to claim that they are more reliable than the satellite companies – the fact is, if the service is installed properly you will have very little trouble with satellite TV (you may lose signal for five or ten minutes during a torrential rain, but even that can be pretty much avoided if you use a slightly larger dish). On the other hand, what cable television subscriber would tell you that their cable service never goes out (or stays out for five to ten minutes at most when it does go out)? Snow accumulation in dishes isn’t as big a problem as you might think, but if you get a really sticky snow it can accumulate on the dish and potentially drop the signal below a usable level, which is a good reason to keep the dish low enough to the ground that a swipe or two with a broom resolves that problem.

Let’s touch on some of the specific problems with the roof-mount method of installation:

  1. Unlike terrestrial television signals, you do NOT get any appreciable signal gain by mounting a satellite dish high off the ground.  A Geosynchronous satellite is 22,236 miles above the earth’s equator.  Do you really think getting it an extra 10 or 15 feet above the ground is going to make any difference, unless you are doing so to avoid a specific obstruction in the path of the signal?  The only valid reason to mount a dish high is if you absolutely need to do it clear a ground-based obstruction, which is rarely the case.
  2. The dish is like a sail against the forces of wind, and also can be moved by ice dams and heavy snow, which means that over time the lag bolts used to screw it into the roof will loosen and allow water to penetrate.  Unless there is treated plywood under there (something almost never used on a roof), the wood will then start to rot, allowing even MORE water to penetrate. That, in turn, will lead to more rot and eventually to roof leaks.  By the time it happens, good luck locating the original installer and trying to hold him responsible.
  3. At least in the picture above, the wire does not appear to be stapled to the roof, but some installers will haul out the staple gun and have at your roof.  That’s even more opportunity for water penetration and eventual leaks.
  4. The wire is going over the eaves at exactly the place you might see ice dams build up in northern climates.  Get a heavy enough chunk of ice frozen around the wire, add a warm day and the forces of gravity, and you may find the wire snapped or detached from the dish.  If you are really lucky the dish and the LNB’s at the end of the arm won’t be damaged, or moved out of position.
  5. In a typical northern winter, there will be days where the dish gets full of snow, and that blocks the signal.  Trust me, you are not going to want to have to get a ladder out every time it snows just so you can sweep off the dish.  You can buy a heated dish to avoid this problem, but then you’re wasting electricity on the days you don’t need it just to avoid a problem on the days you do.
  6. And let’s not forget that you have an ugly wire running down the side of your house, which may or may not be attached in a semi-neat manner, depending on how lazy/incompetent the installer was.
A much better idea: Satellite dish mounted on metal pole in concrete
A much better idea: Satellite dish mounted on metal pole in concrete

Now as I said above, ground installation is often the best, though few installers will offer that option. But here’s the rub with ground installations:  The lower you go, the more likely you are to get interference from nearby ground-based obstructions, such as buildings, other man-made structures, and trees.  If the trees are on your property there is often the chainsaw solution, but most reasonable people have at least a few reservations about cutting down a healthy tree that’s been alive longer than they have just to get a television signal, plus the tree may be on a neighbor’s property, in which case that option probably isn’t open to you, unless you have an exceptionally good relationship with your neighbor.  It’s better to try to find an existing spot in your yard where there will not be any interference with the signal, but that can be pretty difficult EXCEPT during about two weeks out of the year, one in the spring and one in the fall.

When I was searching for information that might help me explain this, I came across this post on the SatelliteGuys.US Forum that explains it better than I could:

Solar outage time is here again-great time to reposition dishes!

That post explains the procedure, and has a link to a program you can run in a DOS emulator to calculate solar outage times in your area (it also has a link to an online calculator, but that has moved here).  I have tried running that program in Boxer under OS X and it seems to work great, despite its age.  I think you could also run it under something like DOSEMU on a Linux-based machine, or as the article suggests, from a DOS prompt on a Windows-based machine (don’t know if newer versions of Windows still allow that but if not, someone’s probably come up with a way to run DOS programs in newer versions of Windows).

The point is that on a certain day at a certain time (the date and time will vary depending on your latitude and longitude) the sun will be right behind the satellite you want to receive.  All you have to do is make sure that your dish will be in a spot that’s in full sunlight at that time — the further from any shadows cast by buildings, trees, etc. the better — and you are golden, at least for that satellite.  If your dish has multiple LNB’s, then you need to find a spot that’s in full sunlight at all times that the sun is behind one of the satellites.  For U.S. dish owners, that means you’ll have to check at three different times during the morning or afternoon, depending on whether you are using the eastern arc or the western arc of your provider, and try to find a spot that’s in full sunlight at all three times.  If no such spot exists in your yard, keep in mind that you do have the option to set up a separate dish and pole for each satellite you want to receive — you don’t have to use the three-in-one combo dish (I will also note that individual dishes are much easier to aim at the satellites, especially for the homeowner that has little or no experience in aiming a dish, but of course some people just don’t want three dishes if they can get by with only one).

If the exact date isn’t convenient for you, you can try a day or two earlier or later.  Remember that in the springtime, if you are earlier, the sun will be lower in the sky than the satellite so you want to beware of shadows near the top of the dish.  Conversely, if you are late on the date, the sun will be higher in the sky than the satellite, so it’s shadows nearer the bottom of the dish that will be closer than they appear.  In the fall, it’s just the reverse – the sun is higher in the sky prior to the exact date, and lower in the sky on the dates following. Sometimes you can’t do it on the exact date because the weather doesn’t cooperate, but usually being a day or two early or late doesn’t affect the result that much.  Where you don’t want to be early or late is with the time.  The sun moves a full degree in the sky in just four minutes (I didn’t believe it either, but check it with a calculator – it’s true!) and that’s quite a huge distance when you are trying to check the position of the shadow of an object that may be several yards/meters away.

Remember that in spring the trees usually don’t have leaves on them yet, so a small shadow from a branch now can mean a full obstruction of the signal to your dish once the leaves appear.  Also, branches get heavier and move in the wind more with leaves on them, so don’t cut it too close – preferably you want your dish in the middle of a nice BIG sunny spot, not a small opening in the trees (unless you only want to watch TV when it’s not windy).  And finally, remember that your dish won’t be on the ground — note the suggestion in the linked article to use a tall stick and a paper plate or pie tin to help make sure the dish itself will be in the sunny area, not just the bottom of the pole.

Sure, you could pay for a professional satellite site survey, but the sun will do it for you for free twice a year, so why not take advantage of it?

EDIT: I’ve found the following article, which includes even more suggestions for finding a spot for a dish that has a clear view of the satellites:
Why certain days in the fall and spring are great times to go out and look at your satellite dishes

I no longer recommend using Asterisk’s Google Voice support — try these methods instead!

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

EDIT (May, 2018): FreePBX and Asterisk users that wish to continue using Google Voice after Google drops XMPP support should go here: How to use Google Voice with FreePBX and Asterisk without using XMPP or buying new hardware.

This article was originally written in January of 2012, and has been heavily edited in an attempt to update it a bit.

Not that anyone probably cares what I think, but anyone who regularly reads this blog (or any of the other VoIP-related blog that cover Asterisk) may have noticed that prior to the release of Asterisk 11, Asterisk’s support for Google Voice had become less and less reliable over time, particularly for incoming calls. You have to do all sorts of “tricks” to make it work, and these usually involve adding delays that don’t always fix the problem, inconvenience your callers, and possibly cause more hangups as people get tired of waiting for you to answer the phone.

Therefore, I suggest that if you are using a version of Asterisk earlier than Asterisk 11, you stop using Asterisk’s Google Voice support completely. Assuming that you feel you must keep using an older version of Asterisk, I suggest trying one or more of the following:

  1. Use YATE as a gateway between Asterisk and Google Voice. See Using YATE to overcome Google Voice issues in FreeSWITCH and Asterisk, this article and this forum thread on YATE in a Flash, and this thread on YATE Tips & Tricks). YATE is what powers Bill Simon’s gateway (mentioned below). See comments by Bill and pianoquintet under this article.
  2. Use Bill Simon’s Google Voice-SIP gateway to handle your Google Voice calls. Some people may not want to rely on an external service for this, while others may very much appreciate having the option. I mention it for those in the latter group. For more information see Bill Simon’s Free SIP-to-XMPP Gateway Easily Puts Google Voice on Your VoIP Phone (Voxilla). While the linked articles talk about using the gateway with a SIP device, it can be used as an Asterisk trunk.  EDIT: As of April 7, 2015 the Google Voice Gateway has been relaunched and there is now a one-time fee to sign up.
  3. If your only issue is with incoming calls, you could use a DID to bring the calls into your system.  But keep in mind that Google Voice does not like it when calls are answered the moment they connect, so in your FreePBX Inbound Route be sure to set the “Pause Before Answer” option to at least 1.  I have found that a 1 second pause is sufficient, but I’m not saying that is the correct value for everyone, or even that everyone will need to include such a pause (some DID providers may delay the call sufficiently before connecting through to your system that the pause isn’t needed).

At this point, any of those would likely produce better results than using the Google Voice support in any version of Asterisk prior to Asterisk 11.

EVERYTHING in this article is my personal opinion.  Nothing here should be taken as a statement of fact.

EDIT:  Ward Mundy reports that he just may have found a workaround for the incoming calls issue — see this thread in the PBX in a Flash forum.

Why do Western Digital hard drive power supplies leak so much AC voltage?

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

We recently changed out a case on a computer power supply.  The new case is metal whereas the old one was plastic, and as I was plugging in a USB cable from a USB hub I got a shock.  Not only that, when I accidentally touched it to the bottom of the computer’s case, the computer power supply completely shut down and would not restart until I physically removed the power cord and plugged it back in.  Since this hub had worked just fine with the old case, it led me to wonder what the issue was.  I put a voltmeter on the shell of the USB cable and measured about 50 volts AC to ground!

To make a long story short, I have four external USB drives plugged into that hub and they are all Western Digital. Every single external hard drive had AC voltage on its USB cable shell (when disconnected from the hub), whereas no other devices had more than a volt or two.

That led me to disconnect the power supplies from each of the hard drives, at which point I made a, um, shocking discovery!

I measured the voltage from the power supply DC plugs to ground.  For this test I plugged them into an outlet on a totally different circuit from the one I plug my computers into, since a friend has suggested that the outlets might be miswired (hot and neutral reversed).  I tested for that possibility and that was not the case, but it was still easier to take them out to the kitchen for this test.  I photographed the results for three of them but a fourth gave similar results.  I’m sorry that the pictures are a bit blurry but if I’d used flash it would have washed out the LED display so the exposure times were a bit longer than I would have liked, given that my hand isn’t all that steady.

Western Digita Power Supply #1 - 44 volts leakage

Western Digita Power Supply #2 - 57 volts leakage

Western Digita Power Supply #3 - 44 volts leakage

EDIT: For a few hours after I first posted this, I had image duplicated as . Sorry about that.

A few observations I noted while testing the voltage:

It didn’t matter which way the AC plug was inserted into the socket – the voltage was the same or very nearly the same (within a couple of volts) either way.

It didn’t matter whether I measured to the center or the shell of the DC plug – the voltage was exactly the same either way (this makes me think the leakage might be through a capacitor or capacitors, since otherwise there would be a DC short).

Whatever voltage I measured at the power supply found its way to the USB plug shell once the power supply was connected to the hard drive.

I measured this on FOUR different power supplies, all ones that came with Western Digital hard drives of various sizes. On three I got the 44 volt reading and on one I got 57 volts.

If it were just one or two power supplies doing this, I’d suspect a flaw in that power supply. But since every single one of them is doing it, I have to think it is something inherent in the design of the switching power supplies used with external hard drives. For some reason this never caused any problem with my old computer or case but this new one (new case) can get really strange if you connect or disconnect the USB hub while it is running and the power cable is connected. I just hate the fact that there is this much stray AC but it must be a problem specific to the hard drive power supplies so I don’t think there is anything I can do about it.

I don’t know of any way to correct this problem, or even if it really is a problem. But I REALLY don’t like it!

By the way, I don’t mean to impugn Western Digital specifically, it’s just that right now all four of the external drives connected to this particular computer are WD’s.  I do NOT know whether or not this problem affects power supplies that come with other makes of hard drives (if anyone wants to test yours and post the results in a comment, I’d appreciate it, but please don’t unless you have worked with electricity enough to know how to do the test safely, since I will not be responsible if you fry yourself or your equipment because you didn’t know how to do the test!).

DynDNS (mostly) discontinues free DNS service

 

Important
This is an edited version of a post that originally appeared on a blog called The Michigan Telephone Blog, which was written by a friend before he decided to stop blogging. It is reposted with his permission. Comments dated before the year 2013 were originally posted to his blog.

Dynamic DNS service selections in DD-WRTOver the years, many people have used DynDNS as a way to get a free domain name that will “track” their actual IP address, even if their ISP changes it.  Apparently that free ride has all but come to an end.  If you read the instructions that How-To Geek posted in their article How To Easily Access Your Home Network From Anywhere With DDNS, you will note that when you go to the DynDNS site now, it looks nothing like it did then, and the totally free option seems to have disappeared.

Apparently if you have an existing DynDNS account you can keep it as long as you don’t let it expire, but if you do let it expire or if you are trying to set up a new DynDNS account for yourself or someone else, the free option is no longer shown. It appears that now the only way to get a free DynDNS account is to sign up for a 14-day DynDNS Pro Free Trial and then cancel it before the free trial period is up. Then, “You may keep one hostname free of charge for trying the Pro Trial.” The problem with this is that you have to provide a major credit card to sign up for the trial. This will be a show stopper for many users (it definitely takes DynDNS off my list of recommended services).

I had recommended using DynDNS in my article, Using DynDNS to solve the problem of keeping a firewall open to remote users at changeable IP addresses. Now I sort of wish I had recommended someone else.

Some home routers support several Dynamic DNS services, and one of the most popular is No-IP. My guess is that they will be the main beneficiary of the decision by DynDNS to make their free service less accessible. I think they have been around nearly as long as DynDNS (if not longer) and I’ve not heard anything negative about them, so I now recommend you check out No-IP in preference to DynDNS, unless you enjoy having to give up your credit card information and then having to remember to cancel a “free trial” within an allotted timeframe.

To those router manufacturers that only offer DynDNS as a DDNS option, please consider adding No-IP (and maybe a few others) as a DDNS option in your next firmware upgrade.  Those that have replaced their router’s firmware with DD-WRT have the option to use DynDNS.org, freedns.afraid.org, ZoneEdit.com, No-IP.com, 3322.org, easyDNS.com, TZO.com, and DynSIP.org (or you can use another “custom” service). I do not know if all of those have a free service offering but I believe that most of them do. So, commercial router manufacturers could offer options other than DynDNS, and I hope they’ll consider doing so.