6 Sep
2005
6 Sep
'05
11:56 a.m.
At 10:18 PM 9/5/05 +0100, you wrote:
Ineed...
I recently won an HP82915 Modem on E-bay (my
first, and so far, only
purchase there).
Tony? E-bay?? Now I know the end of the world is coming! :-)
I was suprised to get it for the opening bid, I though
Lucky me :-)
It wasn't listed as an Integral part, only as an HP82915 Modem. I was
pretty sure that was the Integral modem, one of my manuals mentions it in
passing. When it came, I was certain. Right size board, right connector
(a DIN 41612 socket), plastic cover over the solder side, etc.
I'd have at least one other HP collector to
contend with. It is, you see,
the internal modem for the HP Integral.
Darn you! I keep a constant watch on E-bay for Integral stuff but I
didn't see it!
Anyway, it's a single PCB that fits into one of the Integral's expansion
slots. Cotnains about 20 ICs, most of which I recognise. One odd thing is
that the serial chip used is an 8250, a somewhat odd choice for a
68000-based machine.
Does anyone here know anything about using it?
Not much. It's a 300/1200 Baud modem. ONE sales brochure list it in ONE
place but give NO details or pictures and never mentions it again. The service manuals don't give ANY details about it.
(It's one of those "If it
fails, replace the CCA. If it still fails, replace the whole thing."
Repairing it would probably violate the FCC approval (it would certainly
violate BT appoval for a UK modem). Since I don't intend to connect this
to a public phone line, that doesn't bother me.
That said, the HP Portable Plus service manual (I have it) does give some
repair procedures and a scheamtic for its internal modem (totally
different ot the IPC one, BTW). I does say that certain components
(mostly resistors) must not be replaced in the field, since this could
affect the FCC approval (incorrect transmitter level, etc).
procedures.) To test it they have you install two
modems in the IPC and
plug them into separate phone lines and call one from the other while
running the diagnostics program. The diagnostics program will report No
Carrier, No Dialtone and the like but that's all. There no mention of a
null-modem type cable.
Well, there won't be any form of null modem cable. There are only 2 wires
to the telephone line, and polarity shouldn't matter. However, we had a
brief discussion here a few weeks ago about linking 2 modems without the
use of a public telephone system, e.g. by buying a small telephone
exchange. I am wondering how much is actually needed for _this_ modem.
-tony