[Asterisk-Users] ISDN stuff (was pri pricing)

[Jon Pounder]

Ok couple more questions :

1) the isdn modems (not cards) talk via serial port - according to the 
isdn4linux docs i4l is not needed with these modems since they act like any 
other modem with at commands etc. Are there any out there that actually 
make the raw datastream available ?  Presumably then it would be simple to 
rip apart the serial protocol and make a zap driver for it.

2) any one know of a list of the isdn cards which actually work with the 
north american switch types ? I have seen comments about needing patches 
for that in isdn4linux as well.

3) I am under the impression that with isdn4linux you lose a lot of the d 
channel information like called number, "bulk callerid", etc which are 
things the CAPI project seems to be working towards
Is this actually the case or am I misunderstanding ?


At 10:49 PM 3/2/2003 -0600, you wrote:
>On Sun, 2003-03-02 at 21:30, Jon Pounder wrote:
> > I am still not really clear why the isdn modems that seem so common
> > can't/won't work in this situation. Is it simply an issue of software does
> > not exist ? Does the modem do something other than simply dump the
> > composite digital datastream into the serial port ? I am familar with 
> how a
> > channelized T1 can be output/input via a v35 HSSI port - Does this same
> > concept not extend to the BRI isdn and a regular speed serial port ? Is 
> the
> > issue that a conventional serial port is topped out at 115k and bri would
> > be 64+64+16 ? If so, how does the modem work in bonded bearer channel mode
> > for data ?
>
>A isdn modem dumps the data to the serial port. Since the 16k channel is
>signalling data it is only of interest to the modem. Also there is
>serial cards capable of doing 115K, 230K, and 460K speeds. The last ISDN
>modem I bought was from Cardinal, and it supported up to 460K serial
>speeds, and I bought a SiG 16650 Uart serial card that supported up to
>460K serial. For whatever reason the Cardinal modem dies shortly after
>getting that speed out of it. Also my provider gave 300 hours a month,
>but it was billed by the B channel used so I either had 150 hours bonded
>or 300 hours unbonded. Also the ISDN modems I used all used a form of
>the Hayes AT command set which would end up limiting them to the same
>problems that a standard modem has.
>
>I believe if you look at the list you will find quite a few people in
>europe doing ISDN in asterisk, but they are using cards that terminate
>ISDN and not external units. The difference is that they sit on the bus,
>and don't have to make a serial Uart that is rate limited, nor limited
>in how you communicate with it.
>
>--
>Steven Critchfield <critch at basesys.com>
>
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