[Info-vax] VAX RDMs (Remote Diagnostic Modules)

[Johnny Billquist]

On 2011-11-17 15.07, Bob Koehler wrote:
> In article<1c7dp8-e55.ln1 at Ubuntu.mike-r.com>, Henry Crun<mike at rechtman.com>  writes:
>
>> Actually I seem to recall (could be wrong, though) that LA36's were current
>> loop, and could not talk to a standard modem. You would probably need an LA120,
>> or (slower) LA70(?)
>> I remember the RDM on a PDP 11/70 - DEC could only dial in if we switched from
>> local to remote console (IIRC a rotary switch on the front panel)
>
>     Our LA36 and LA120 were current loop, because that's what out VAX
>     11/780 and various PDP-11 required as consoles.  But the LA120 was
>     available without the current loop option, and I think the LA36 was,
>     too.

By the way, as far as most PDP-11 goes, the choice between current loop 
and RS-232 was selectable by having different cables to the DL11.
The DL11 did both, and you just had different wiring in the connector to 
the DL11 to get either.

I never played at that level on a VAX-11/780, so I don't know how it 
looked on that one. The VAX-86x0 machines only have RS-232.

	Johnny