[Asterisk-Dev] Channel bank w/ bri card and Zaptel

[Steve Brown]

Steve,

I tracked down the BRITE 3DS0 info first. It's Committee T1 TR #7. It 
has 9 pages and the pdf cost me $42. It is somewhat of a kludge designed 
to work with the old D-channel bank. Basically, the interesting bits are 
in pos 6 & 7. Bit 8 (low order) is always "1". My cb doesn't seem to 
support this. I agree that you would want to support all the mux 
schemes, including 3DS0.

Also, the protocols supported by libpri seem to be, among others, NI-2, 
not NI-1, which is needed for bri's, at least, where I live. I haven't 
really looked at the protocols used in Europe. The full NI-1 doc from 
Telcordia is about $400 and change. I may not be that ambitious. The cb 
only cost $75 on ebay and 6 bri cards another $90.

I've spend a lot of time looking at one of the low-level hisax drivers 
while trying to get a Eicon Diva 2.02 card to work. I don't think the 
low-level hisax <-> zaptel interface would be very difficult.

For me, the first step is to cleanly support the various d channel mux 
schemes in zaptel.

My hope is that some of the list experts might find this interesting and 
provide hints on what to do next.

Steve


Steven Critchfield wrote:

>Just so you know some terms listed in the Adit ISDN BRI card
>documentation;
>
>4:1 TDM is where 4 BRI lines share a DS0 for the D channel
>
>3DS0 BRITE is where the ISDN BRI uses 3 DS0 channels and the D is on a
>DS0 of it's own.
>
>Don't know more, but this hopefully will help if you want to shake down
>some documentation more than what this says. It would be nice if both
>kinds of muxing are available.
>
>Out of curiousity, wouldn't this be the same type of information as is
>in the D channel of a PRI, and therefore maybe mostly implemented
>already in libpri?  
>
>On Thu, 2003-04-03 at 12:03, Steve Brown wrote:
>  
>
>>I have a t100p and Premisys bank w/ bri card. The bri card has 8 u ports 
>>that can be configured for either terminal or network. Each port uses 3 
>>ds0 channels, one for b1, b2 and d. The d channels of four ports can be 
>>multiplexed on the same ds0. Each of the 4 ports is assigned 2 bits in 
>>each ds0 byte. This seems pretty standard for other banks too.
>>
>>Given zaptel support for the multiplexed d channel, it might not be too 
>>difficult to build a low-level hisax driver for zaptel and let 
>>isdn4linux do the L2/L3 stuff. I realize that i4l only does terminal 
>>(not network) protocol, but it's a start.
>>
>>I've experimented with an isdn phone and nt-1. L1 syncs up and a dump of 
>>the d channel (configured as clear) shows the phone trying to establish 
>>L2 w/ switch. All the bits seem to be where they belong.
>>
>>If you already have a channel bank, this seems like a tidy way to add isdn.
>>
>>Has anybody familiar with zaptel and/or hisax looked into this?
>>
>>Steve
>>
>>
>>
>>
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