Quote:>We are interested in the possibility of using ISDN BRI (128Kbps) for
>remote access/remote control of a PC. We would also like to upload
>binary files (300Kb) to a central location from one or two remote
>sites through the ISDN link. We are currently using PCAnywhere
>5.0/DOS for this. Will this software support ISDN remote access and
>also file transfers? Is there a better DOS product on the market
>which can accomplish this?
If you use one of the ISDN TAs which looks like an AT command set modem, that
should work. Many TAs will only make such connections using V.120 (V.120 was
designed for carrying async data over ISDN, designed to replace modems without
affecting the application, exactly what you are looking for.)
The problem is that V.120 is a 64K protocol. You can't run it over two
channels. I am pretty sure that you can configure a pair of Motorola
Bitsurfers (one at each end) to use the AIMUX protocol, and get the 128K
connection you seek.
Now, that leads to a different problem: A 115,200 PC async serial port is only
carrying a 92,160 kbps payload. The rest is async start and stop bits which
are never sent over the ISDN. Your 6-foot serial cable will be a slower
bottleneck than the line. In fact, you will use less than 50 per cent of the
second B-channel.
So you need to get high-speed serial cards for the PCs, upgrade the BitSurfers
to Revision L or M software, and then:
Set the serial cards to 115,200.
Send the AT command string to <switch to 230,400 bps and store the setting>
Set the serial cards to 230,400.
Laurence V. Marks
IBM Corp. - Research Triangle Park, NC
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