Re: Digital Modems (fwd)
Matthew S. Crocker (matthew@crocker.com)
Thu, 19 Sep 1996 09:38:40 -0400 (EDT)
> +---------------------------------------------------------------------+
> | PM-3 Chassis |
> | |
> | +-------+ |
> |+---------+ +--------+ | High | +-----------------+ |
> || Digital | | Digital|---| Speed |---| Routing | |
> - PRI --| Switch |--digital--| Modem |---| Back |---| Engine | |
> |+---------+ +--------+ | Plane | +-----------------+ |
> | +-------+ |
> | |
> +---------------------------------------------------------------------+
>
>
> Digital data in, through digital modem, onto digital backplane, through
> routing engine to ethernet.
Yes, but in the case of a v.34 modem connecting to the digital modem you
have a datastream on the B channel which is a digital PCM representation
of and analog (v.34) signal of a digital data stream (RS-232). So you
can convert Digital PCM data directly into serial data and jump over the
analog v.34 signal? Or, do you covert the PCM data stream back into
analog (v.34) and run that through a modem to get the RS-232/PPP ?
I see how it works pure digital for ISDN because it is pure digital. I
can't see how you can bypass the PCM -> analog codec conversion, unless
you do it all in software on the DSP.
-Matt