Back in the old days (couple years back) I had a ethernet-less "serial"
network running at 115.2K then later at 230K with over 75 foot of radio
shack cat-3 cable. I ran the data wires red/green, signal ground black,
case ground yellow.. worked great.
Now, of course, ISP's aren't supposed to be sleazy, so I'd never do this
(and it didn't have any modem or flow control signals).
I can't see why you couldn't use 5-10 foot of 3-pair cat-3 for hookin up
lines to a PM, though there might be some wires I am forgetting (personally
I bought tons of db-25 to db-25 to hook to my Cardinals - and never
regretted it for a moment.
TTYL
JS