Subject: Still need DHV11 (M7940) docs
To: None <>
From: Rick Copeland <>
List: port-vax
Date: 09/30/1998 10:40:24
Dear Vax Gurus,

I am trying to connect a VT220 to a VAX 11/785.  The 11/785 has a frontend
processor which is a pdp 11/03.  The 11/03 has a Serial Line Unit (SLU, aka
DHV11/M7940) card in it that is the point of connection for the mainframe
console.  The problem I am having is getting any kind of documentation on
the DHV11 (M7940). Several people have posted that they will at some time
post this information but haven't yet. Also some have suggested that the pin
outs of the M7940 are the same as the unibuss DHV11 but it appears that this
is not the case although this is somewhat hard to verify because I may not
have the jumpers on the M7940 in the correct position.  The cable coming off
of the DHV11 (M7940) is a DEC part number BC03L-05, which has a 40 pin berg
connection on one end (M7940 end) and a 25 pin male connector on the other
end.  It would be my guess that this would imply the use of a null modem
(both VT220 and console port being DTE's) cable between the console and the
VT220 but this does not work regardless of the baud rate set or other
configurations set at the VT220.  I have several of the DHV11's (M7940's)
and a M8017AA, a complete spare of the front end processor and cable, so I
have swaped everything at some point to verify that a bad card or card
cage/power supply is not the problem.  This of course points me back to the
configuration of the DHV11 both jumbers on the board and cable.

Can anyone give me a hand on this one?

Thanks in advance.

Rick Copeland
Information Systems Manager
InterMag, Inc.