[Info-vax] DSW41/42 option

[Richard B. Gilbert]

John Wallace wrote:
> On Oct 12, 6:46 pm, Jan-Erik Söderholm <jan-erik.soderh... at telia.com>
> wrote:
>> Volker Halle wrote:
>>> A DSW41/42 is a SYNCHRONOUS WAN device. You can't configure this
>>> device with standard OpenVMS drivers, you need to install the VAX WAN
>>> Device Drivers kit.
>>> Volker.
>> And, what are you supposed to actualy *do* with it ?
> 
> You can talk DECnet (specifically, DDCMP iirc) to a compatible DECnet
> box, or X.25 to the outside world, typically.
> 
> Traditionally, if you got one, you knew what it was going to be used
> for.
> 
> Were these things supported for IBM interconnect or was IBM stuff a
> different kind of synchronous?

ISTR that IBM used BiSynch!  That was short for Binary Synchronous.  You 
started a transmission with two or three SYN characters to allow the 
receiving end to get bit and character synchronization.  The last SYN 
was followed, I think, by an STX (start of text), text, and then ETX to 
end the transmission.

I once had to code "drivers" for BiSynch on an IBM System/7.  I borrowed 
the logic and protocol from a driver written for IBM System/360 and 
coded it in System/7 assembler.  I forget exactly what we used it for.