🚀 go-pugleaf

In message <146d26b47@expl.demon.co.uk> Michael Sanders wrote:

> The whole point about ISDN is that its a digital transmission network
> therefore the conventional MODEM-PSTN-MODEM setup is useless because you
> don't need to convert to analouge, you just send the straight digital data
> stream down the line.  

Yep, but there's no reason why the TA shouldn't use the Hayes AT command set. 

> The TA (Terminal adapter) connects your computer to the ISDN line at a very 
> fast data rate, upto 128Kbaud per sec
 
Very fast? 128k baud is very fast? I call anything over 1 Gbaud very fast.

> if using X25 and both data channels on ISDN 2!
 
They're called 'B' channels. IIRC there are some faster channels on the
line, but you're not allowed to use them :-(

> It also dials the number and sets the line up (using the D channel
> I believe).
 
Yes. It does this VERY quickly. No more waiting for the modem to train :-)

> Therefore to use ISDN you need a suitable TA card
 
 Not necessarily a card. You can get an external TA that you can connect via
the serial port (which will do 115k baud). ISTR some of the more expensive
units also have a parallel interface, if 115k is too slow for you (EPP will
go up to 2 Megabytes / sec, or 16 megabaud). There is one last possibility,
you could use a 10baseT <> ISDN bridge (intelligent one, of course)

> to link computer to ISDN and a software, like ISDN manager on the Mac, to 
> control said TA.  Your comms s/w must also support the ISDN card.  

If you TA supports the Hayes AT command set, it will pretend to be a normal
modem (only it will go like s**t off a shovel)
 
> I may be wrong but I didn't think there was any s/w on the Acorn that could
> do this, I hope I'm wrong!
 
I think there's no reason an external TA that supports the Hayes AT command
set should not work with current comms s/ware. 

BTW: While in Germany a few days ago I say an ISA ISDN adapter for less than
UKP 100. Pitty it won't work on an RPC.


Pat.

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