Univac,
Burroughs and HP all had their own variants of polled block mode
terminals through synchronous comms lines.
Yeah, once you get into the weird polling schemes and "multiple
terminals hanging off a single modem" daisy-chain craziness, then
you're really getting into weird territory.
THere is a little information on the HP scheme on the Australian museum
site (
http://www.hpmuseum.net/). From what I remember there was a
device that plugged into the 50 pin connector on the HP terminal (this
conenctor was essentialyl RS232 signals and power). There was a special
unit for the 'first in the chain' which also had a DB25 connector to the
modem. The other units were daisy-chaiend and connected to the 'first'
oen with DA15 connectors.
I think I have one of the 'first in chain' units, but I am not sure what
I will use it for...
There was annother HP networking thing, the name of which I cannot
remember which again connected to the 50 pin port of terminals with
suitable firmware. All I can remember about it is that it used French
telephone conencotrs (!).
HP also had their own network called 'SRM' IIRC. The origianl
implementation used the 'smart' comms card for the HP9000/200 (DIO bus)
machines with differnet firmware. Again there was some device that
conencted to the 50 pin connecotr on said card and which let you
interconnect them (using coax cable?). Later there was a DIO card which
inclcued htis 'transceiver' and which jsut had a BNCH connector on the
bracket. Again, some information on the Australian site.
-tony
