25 Dec
2003
25 Dec
'03
5:52 a.m.
At 12:35 25/12/2003 +0000, Jules Richardson wrote:
Merry Christmas to all!
reciprocated!
Obligatory pre-feast Christmas posting...
post feast, pre-snooze quick mail read... (am I addicted?)
[snip, this re Datel 4961x's:]
The rear of the case has a 25 pin DTE socket, a
telephone pass-through
socket, PSTN socket for connection to the network - and also a
mysterious "PC" socket (same type as used for the phone network
connection). Any idea what that's for? ("Private Circuit" maybe)
Private Circuit is probably correct. I seem to remember that circuits were
provided using standard BT phone sockets, but using Pins 1 & 6 (instead of
2 & 4 on a PSTN line). This would necessitate using different wiring or
connections on the DCE.
The front has push-switches for 4800 baud operation,
plus AL, ST, RDL
and DL. I assume ST is self-test, but I don't know what the others are.
There are status LEDs for 4800 operation, DSR, RFS, TD, CD, RD and test.
Those all make sense.
Analogue Loopback, Remote Digital Loopback, Digital Loopback, spring to
mind, but I could be wrong. BT equipment often had built in test modes.
I remember I never got one of these to talk to a remote
modem of any
type. I'm wondering if they're supposed to be used in pairs (or talk to
some specific remote equipment that I don't have) and use some sort of
non-standard data compression, or even encryption.
As you have got two of them, have you tried just hooking them directly back
to back to see if they talk? In private circuit mode, you should get at
least get CD light on if they do, but they might need power across the line
to see the signal - a 9V battery is usually good enough for a quick
test. Of course, they might need one of those millions of DIP switches
changing to use in this manner...
Any ideas anyone? Anybody know of any UK telecoms lists
where there may
be people who can help?
Try asking on one of the uk.telecom newsgroups (probably uk.telecom itself)
- it's been a good while since I hung out on there, but they tended to be a
knowledgeable bunch, with a definite interest in old (albeit telecom) hardware.
Rob.