Asterisk with a GSM Gateway.

Jaden

Clever me. I have a Wildcard TDM400P (4xFXo ports) in my Asterisk server, and I thought I'd hook up a GSM gateway (Telecom GSMRoute+, dual SIM) to 2 of the ports, and make cheap landline to mobile calls, by diverting all mobile calls out through these 2 SIMs.

All installed and setup, and I make a call. Asterisk server hands the call off to the GSM gateway, and it connects me.

Disco! Now instead of 15c per minute from landline, I'm paying 8c per minute (my O2-O2 rate).

The problem is that if I hang up the first call. The GSM gateway doesn't detect this, and keeps ringing. Only resetting the device allows another call to be made. If I plug a standard phone into the port of the GSM gateway, I can dial, hang up, dial and so forth without issue. It seems to be able to spot a phone going on hook, and knows to terminate the call. Plugged into any FXO port, it doesn't.

Another oddity is that when I plug both lines into FXO ports, FXO port 1 is detected as "off-hook" by the GSM gateway. If this port is in use, then FXO port 2 uses the second SIM, no problem. Again, once this call is finished, the GSM gateway doesn't detect the FXO port as having hung up.

I've tried all kinds of things in ZAPATA.CONF and ZAPTEL.CONF, to no avail.

Anyone got any ideas?

liamo

Just a thought ...

Is the GSM Gateway <--> TDM400P an FXO <--> FXO arrangement?

Is that even allowed? Should it not be FXS <--> FXO ?

Like I said , just a thought. (I'm an Asterisk hobbyist not a Telecomms engineer so don't slate me if I'm wrong )

Regards,

Liam

Jaden

TDM400P has FXO ports using FXS signaling. I think this is correct, but I have a mental block about FXO/FXS.

sirlinux

does your gsm gateway do polarity reversal? thats the easiest way, otherwise try configuring progress detection for busy tones. Havent tried one of these yet but they look good.

http://www.junghanns.net/en/GSM-PCI_produkt.html

Also there are some nice gsm -> sip gateways that do the business, digital -> analog -> digital can be messy.

Blaster99

The GSM gateway has FXS ports or it wouldn't work with a phone. An FXO port emulates on/off hook and expects a dial-tone. FXS provides dialtone and waits for off-hook type of thing. So in principle it should work. I have never done it so you might need to cross some cables or something.

I've incidently thought of looking into a GSM gateway for Asterisk or whatever. I would perhaps have expected something along the lines of that German stuff you linked to, which does it all in one go. It seems very difficult to get prices for this stuff. How much does this kind of kit cost?

jimmycrackcorm

This is interesting - I have a load of GSM modems - can I connect them to asterisk to perform mobile out calls?

bhickey

jimmycrackcorm wrote:

This is interesting - I have a load of GSM modems - can I connect them to asterisk to perform mobile out calls?

If you can plug an analogue handset into them and dial out then you should also be able to attach them to an FXO port in an Asterisk server and do the same thing.

sirlinux

jimmycrackcorm wrote:

This is interesting - I have a load of GSM modems - can I connect them to asterisk to perform mobile out calls?

if they have sound on them yes... but it's not that straight forward.

Jaden

The device does polarity reversal (and it's on, with a 200ms pulse), but the GSM gateway doesn't seem to "hang up" when a call finishes. It's only when you either power cycle it, or plug in a phone and hook/unhook it that it sets itself to take calls again on the port. It seems to me that the Asterisk server isn't telling the GSM gateway that the call is finished.

The GSM gateway I'm using is dual SIM, and only costs a couple of hundred quid. Some solutions I've seen are more like two grand, so I'm gonna plug away at this thing for a while yet.

Someone must have seen an issue like this before.

My Zapata.conf:
signalling=fxs_ks
rxwink=100
callprogress=yes
busydetect=yes
hanguponpolarityswitch

My Zaptel.conf:
# Span 1: WCTDM/0 "Wildcard TDM400P REV E/F Board 1"
fxsks=1
fxsks=2
fxsks=3
fxsks=4

I'll post a progress report if I get anywhere. At the cost of one of these GSM gateways, I pays for itself in a couple of weeks.....

Blaster99

Yes, do let us know. I'm interested in setting up something similar.

sirlinux

change as follows and give it a try

hanguponpolarityswitch=yes
busycount=4 (or try 2 if your a bit mad)
progzone=uk (dont think this actually work with anything but us tones....)

is the card seeing the polarity reversal? sounds maybe like an impedance setting problem, whats your gsm gateway set for? and your tdm card?

sirlinux

woops, hit submnit a bit early
you need to mess with the opermode= parameter when you modprobe wctdm
modprobe wctdm opermode=
see wctdm.c for the list of countries
also make sure etc/zaptel.conf is setup properly

Jaden

After several hours of mucking about, I found out that my GSM Gateway uses Loopstart to detect clear down. So I've dumped Kewlstart for Loopstart.

Still no joy. Keep plugging away.....

I'll trying some of the suggestions posted by Stephen.

Here are my configs thus far:


Zapata.conf

echocancel=yes
echocancelwhenbridged=yes
echotraining=400
callerid=asreceived

signalling=fxs_ls
group=0
context=from-pstn
answeronpolarityswitch=yes
hanguponpolarityswitch=yes
callprogress=yes
busydetect=yes
busycount=4
channel => 1-4

Zapata-auto.conf

; Span 1: WCTDM/0 "Wildcard TDM400P REV E/F Board 1"
signalling=fxs_ls
; Note: this is a trunk. Create a ZAP trunk in AMP for Channel 1
context=from-pstn
group=0
channel => 1

signalling=fxs_ls
; Note: this is a trunk. Create a ZAP trunk in AMP for Channel 2
context=from-pstn
group=0
channel => 2

signalling=fxs_ls
; Note: this is a trunk. Create a ZAP trunk in AMP for Channel 3
context=from-pstn
group=0
channel => 3

signalling=fxs_ls
; Note: this is a trunk. Create a ZAP trunk in AMP for Channel 4
context=from-pstn
group=0
channel => 4


; Span 2: ZTDUMMY/1 "ZTDUMMY/1 1"



Zaptel.conf:

# Span 1: WCTDM/0 "Wildcard TDM400P REV E/F Board 1"
fxsls=1
fxsls=2
fxsls=3
fxsls=4

# Span 2: ZTDUMMY/1 "ZTDUMMY/1 1"

# Global data

loadzone = uk
defaultzone = uk