Open source Telephony Cards

[ali_asadzadeh]

Hi,
I want to know is there any open source hardware for Telephony Cards being used with asterisk,
I mean something like this
http://www.digium.com/en/products/telephony-cards

or if not,is there a path for showing what's required?

[coppice]

You can find the Tormenta 2 card (4 x E1 or 4xT1) design as as open source package on the web. At www.rowetel.com you will find blackfin based open source hardware to run asterisk with analogue ports. The early Digium 4 port analogue cards are little more than an implementation of the reference designs of the main chip from TigerJet, and the SLICs from Silicon Labs, so most of that can be copied without any IP issues.

[PeterFW]

or if not,is there a path for showing what's required?

What do you want to to?
Connect a bunch of ISDN phones allready installed to a PC.
Connect a bunch of analog phones allready installed to a PC.
Connect a bunch of ISDN and analog phones allready installed to a PC.
Install a bunch of phones and wires and connect them to a PC.

[NiHaoMike]

Probably of most interest is reusing analog phones since they are very common and cheap.

Apart from DACs and ADCs, you'll need some voltage step up for the line and ringing voltages, and an impedance matched coupler circuit. The last part is very important as poorly matched impedance will cause an annoying echo on VoIP calls. (And if you plan to use a speakerphone, you'll need some DSP as well.) Not exactly trivial but still well within in the reach of hobbyists.

[ali_asadzadeh]

Thanks coppice  , I couldn't find the (4 x E1 or 4xT1) on rowetel, would you place a direct link in here.
Also I want a complete open source VOIP system, we can run the asterisk on the beagle bone black, so now what will remain is the open source VOIP phones and Telephony Cards for connecting analog and VOIP phones to the system,
Is there an open source VOIP phone too?