Asterisk hack: make your Google Talk client invisible

It’s been a too-busy-to-write week, but I found some time the last few evenings to brush up my C coding (only hacking at this point, really) to make Asterisk 1.8 do something I’ve wanted from the beginning: Google Talk’s invisible mode for the Google Voice integration.

Quick background: Google wrote a variety of XMPP extensions to make Google Talk do voice and a bunch of other non-standard XMPP things. One of those things is what Google calls “shared statuses,” which also includes invisible mode–the ability to be online but set your client as invisible so that others can’t see you, but could chat with you.

You might want to use this feature if, like me, your Google Voice number is attached to your main GMail account. I don’t use the chat features but I appear online to anyone who has me in their contact list, as long as Asterisk is logged in, and that has the potential to draw unwanted instant messages (that will never get answered).

Note: I want to reinforce that this is a hack. The code is clean enough, but this is only useful for Google Talk and is only implemented as a set of Asterisk CLI commands. Furthermore, this functionality would probably never be implemented in Asterisk’s res_jabber because it’s Google-proprietary. On the other hand, if any Asterisk developers want to run with this, go for it! I don’t guarantee that this code will work for you and if your Asterisk process segfaults, stop using it.


Apply this patch against Asterisk’s (or trunk, currently) res/res_jabber.c by downloading the patch to your Asterisk source directory and running patch < res_jabber.patch . You may have to tell it to apply the patch to res/res_jabber.c.

Rebuild (or build) Asterisk. If you are rebuilding, just run make after applying the patch. You should see make build the res_jabber module. Then make install and restart Asterisk.


At the CLI, you can issue jabber set invisible on asterisk to turn on invisibility for the Jabber connection named “asterisk.” If you don’t know what your Google Talk XMPP connection is called, just issue jabber show connections and find out. You can set your connection visible again with jabber set invisible off asterisk.

Now, here’s another thing that is really hacky: Google Talk only seems to apply the visibility/invisibility change if you are toggling. Here’s what I mean: if you were invisible, and logged out, then logged back in, Google still thinks you are invisible–but you’re not! So in that case, if you jabber set invisible on ..., it doesn’t do anything, until you first set it off and then back on again. I think I know why this is happening and it has to do with res_jabber sending standard <presence> information at login rather than Google’s special shared-status presence scheme. If you want to be sure you are invisible, just start off by setting invisible off and then set it on. For me, that works every time. (I’d be grateful for someone who really knows all about this to fix it up and make it work right, the first time.)


I got the idea from this year-old blog posting about enabling Google Talk invisibility in Pidgin, which refers to the official documents published by Google on how it works.

Update on rotary phone refurbishment

In my last post, I suspected problems with the rotary dial on the Automatic Electric Monophone model 40, and a wiring problem on the Northern Electric 302, both of which kept me from being able to successfully pulse-dial through the HandyTone 502 analog adapter.

After a quick wiring check on the 302 and a lot of tweaking and oiling of both dials, I have to throw in the towel on getting these two to pulse-dial. Both need to have their centrifugal governors (the part that regulates the dial’s return speed) adjusted: the 302 pulses too slowly and with some irregularity, and the Monophone 40 pulses too quickly. I have read that telephone technicians of the past had to practice dial repair for a week under supervision before becoming competent at it. That is to say, the final touches are definitely beyond my skill level, and with a voice-driven workaround available, I’ve decided to call these phones “complete”–for now. I’m a tinkerer and may get adventurous some day and rip the phones apart once again.

A brief review of the Grandstream HT-502 ATA

The used HT-502 2-FXS analog telephony adapter I bought from eBay arrived earlier this week, and I hoped that by this time I could write about two functional rotary dial phones happily dialing out through this device.

No such luck, but the HT-502 is not to blame. The Northern Electric 302 seems to be mis-wired, because the ATA isn’t detecting the pulse dialing at all. I’ll have to open it up and dig in this weekend. The Automatic Electric Monophone 40, on the other hand, is wired correctly but needs some adjustment: the upper digits (7 through 0) sometimes miss a click, resulting in mis-dialing.

Image from Grandstream.comThat said, I’m already prepared to give the Grandstream HT-502 ATA very positive reviews. In fact, I might like it even better than my trusty Cisco-Linksys-Sipura SPA3102.

You can read about the device on Grandstream’s web site. Here are the unmentioned features that I really like:

  • It accepts rotary/pulse dialing, without any special configuration or modification. This was the reason I bought it, and indeed, it works. The HT-503 (1 FXS and 1 FXO port) can accept pulse dialing on its FXS port, also.
  • On an active call, it accepts rotary-dialed input and converts to SIP DTMF codes. Thus you can navigate a menu tree with your rotary phone, as long as you don’t need “*” or “#”.
  • You can configure the device with a touch-tone phone (real touch-tone; “*” required), web browser, or telnet. You can also provision the device using TFTP like the “big guys” do.
  • It has an excellent debugger. In the Advanced menu, enter the IP address of your syslog server (prerequisite: set up a syslog server), and set the verbosity to DEBUG. The floodgates will open and you will be able to see every action the device performs or receives, including dialed digits from the analog ports. This is how I was able to see where my rotary dial was sticking.
  • The device can pull its own firmware upgrades over the Internet. Nice if used carefully.
  • It’s super easy to configure. I followed documentation to factory-reset the device, hooked up a laptop to the LAN port, and reconfigured it for my own network in about 5-10 minutes. 
  • Lastly–and this is a rather obscure bonus–it uses the same power supply specifications as the Cisco-Linksys SPA devices. This hardly matters except that I have one of these–a wireless bridge for Cisco SPA devices with pass-through power. I’m planning to make the HT-502 WiFi.

The HandyTone 502 has made a good first impression and I’m looking forward to getting my rotary phones fully working on it.

A new old phone and rotary dialing, revisited

During the holidays I received and lightly restored another beautiful telephone from the 1940s, this Automatic Electric Monophone model 40:

ae40.jpgAutomatic Electric was an independent supplier of telephone equipment throughout the 20th century, eventually being purchased by GTE, and in direct competition with the Bell empire (or Western Electric, Bell’s equipment division) throughout its existence. The community-written Wikipedia article tells more of the story.

Some details about this Monophone:

  • Manufactured from 1939 to the mid-fifties, but I can’t find a stamp on the inside or outside to date it.
  • The coiled handset cable would typically indicate a later model, but the nicked-up brass screws inside the handset where the cable is connected suggest that the coiled cable was an upgrade or repair at some point in this phone’s lifetime. So it may be an old phone body with a newer cable, or it may be a later model, all-original.
  • The dial plate seems to be uncommon. Browsing many pictures of AE model 40s on the web, I haven’t seen any others with white-numbered, black dial plates. Also, it has no alphabet markings, only digits.
  • It’s all Bakelite, and heavy. The Northern Electric 302, with a thermoplastic shell, is almost a full pound lighter. External data: someone weighed their own collection of phones.

The Northern Electric 302 and the Automatic Electric Monophone 40 ready to duel:
ne320-ae40.jpgThe AE40 works fine and will be a new addition to the analog remix, but I decided to do one more search for VoIP analog telephony adapters (ATAs) that will accept rotary/pulse dialing. Recently, a commenter suggested UTStarcom adapters, but others report of an ATA that is still in service and accepts rotary dialing: the Grandstream HT-502/503. I have a 502 coming from an eBay auction and will report back on how it works out.