PBX (or something) for modem testing

dkgrizzly at thewaffleiron.net dkgrizzly at thewaffleiron.net
Thu Dec 5 09:02:13 CST 2019

As an example of a unit that should work:

The FXS cards output out the back using a 50-pin / 25-pair AMP telephone cable. Look for RJ21 breakout, RJ21 octapus, or RJ21 hydra cables.  You could also go the 66-block & AMP cable route if you want something more permanent that is mounted to a wall somewhere.  I was lucky to find a RJ21 breakout module on ebay that had 6 "8P8C" jacks in a tiny housing.

The important bits are the CMG card, and the 8C cards.  You can get by with earlier FXS cards, but the 4th & 5th gen FXS cards don't do caller ID and aren't as flexible on what line types they can simulate.  The ADIT itself isn't a PBX, but a channel bank.  It just converts between analog and digital formats, without an asterisk or other switch to talk to, it can't do much beyond convert between T1 lines and analog extensions.  The CMG card talks to asterisk over MGCP, and will give you 48 virtual T1 channels, you can sent them out the T1 jacks on the back of the ADIT, or convert some of them to analog FXS channels.

Karl Brose over on the c-netlist ( https://groups.io/g/c-netlist ) is an expert of sorts on these units and has been an immense help getting mine working.  He has a patched Asterisk source tree with a modified MGCP driver called chan_xgcp that makes everything work better.  I was able to get his help setting up my system for VCF Midwest in Chicago, he provided the drivers and example configs that worked well.


-----Original Message-----
From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Jim Brain via cctalk
Sent: Thursday, December 5, 2019 1:21 AM
To: cctalk at classiccmp.org
Subject: Re: PBX (or something) for modem testing

On 12/4/2019 7:47 PM, David Kuder via cctalk wrote:
> If you go the Pi route, a ADIT600 is a good option. Get one with three 
> FXS 8C cards and a VOIP Router card. This works great for upto 28.8 / 
> 33.6 from my experience.

Been reading up on all the units.  On this one:

Do you have to have a VOIP card?  I just want to talk within the PBX.

Where does one source those connectors for the various lines?

Can an 8B card be OK (I see some on eBay)?


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