Posted: Thu Apr 03, 2003 6:03 pm Post subject: [Asterisk-Dev] Channel bank w/ bri card and Zaptel
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?
Posted: Thu Apr 03, 2003 8:36 pm Post subject: [Asterisk-Dev] Channel bank w/ bri card and Zaptel
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:
Quote:
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?
Posted: Fri Apr 04, 2003 1:15 am Post subject: [Asterisk-Dev] Channel bank w/ bri card and Zaptel
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:
Quote:
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
>
>
>
>
>_______________________________________________
>Asterisk-Dev mailing list
>Asterisk-Dev@lists.digium.com
>http://lists.digium.com/mailman/listinfo/asterisk-dev
>
>
Posted: Fri Apr 04, 2003 1:36 am Post subject: [Asterisk-Dev] Channel bank w/ bri card and Zaptel
Quote:
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
Quote:
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?
The BRITE configuration is much more prevalent than the 4:1 TDM version
among several manufacturers of ISDN extension equipment. The D channel
information contained in the third DSO of the BRITE grouping is 1/23 of
the PRI signaling channel. The 4:1 TDM signaling DSO contains 4/23 of a
PRI signaling channel. It's conceivable that the libpri could be
modified to handle the BRITE/4:1 configuration. This would entail adding
code to interleave D channel information from the dedicated DS0's on the
T1 and a configuration line to group DS0's and designate DS0's carrying
D channel information. Creating a BRITE/4:1 version of libpri would
definitely provide * users with much needed options for connecting ISDN
desksets as well as equipment such as video conferencing systems and 56K
modem terminations.
Posted: Fri Apr 04, 2003 2:36 am Post subject: [Asterisk-Dev] Channel bank w/ bri card and Zaptel
On Thu, 2003-04-03 at 19:36, George Bean wrote:
Quote:
> 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?
>
The BRITE configuration is much more prevalent than the 4:1 TDM version
among several manufacturers of ISDN extension equipment. The D channel
information contained in the third DSO of the BRITE grouping is 1/23 of
the PRI signaling channel. The 4:1 TDM signaling DSO contains 4/23 of a
PRI signaling channel. It's conceivable that the libpri could be
modified to handle the BRITE/4:1 configuration. This would entail adding
code to interleave D channel information from the dedicated DS0's on the
T1 and a configuration line to group DS0's and designate DS0's carrying
D channel information. Creating a BRITE/4:1 version of libpri would
definitely provide * users with much needed options for connecting ISDN
desksets as well as equipment such as video conferencing systems and 56K
modem terminations.
I'll just say, I don't know how prevelant any kind of service here would
be. I know the BRI card for the ADIT 600 supports both. I'd assume the
same would be true with the Adtran unit since they seem to be fairly
comparable.
As for your math, it is slightly wrong. PRI is 1 64K D channel for 23 B
channels. BRITE places the normally 16K D channel for 2 B channels on a
64K link. If you want to compare it, BRITE is 2/23rds of a PRI. The 4:1
puts 4 D channels on a single 64K channel. The 4:1 uses one 64K channel
for 8 B channels, or 8/23rds of a PRI. This gets you 4 BRI lines in 9
DS0 channels, or 8 BRI lines in 18 DS0s and have a few DS0s left over
for analog.
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