[net.micro] modems that are "powered by the phone line"

lauren%lbl-csam@vortex.UUCP (06/22/83)

From:  Lauren Weinstein <vortex!lauren@lbl-csam>

Greetings.  I'm pretty sure that this topic has come up before,
but just for the record...

It is *generally* not advisable to purchase "powered by the phone line"
modems.  Many of these units require every last bit of power that the
"typical" local loop can provide, and, unfortunately, many loops fall
short of "typical".  Voltage/current on longer loops can be rather low, often
low enough to cause "glitching" (or occasional/frequent complete connection
loss) of modems powered from the loop.

Granted, some of these modems may work just fine in some locations --
but if you ever move you may find that your new phone lines do not
provide enough juice to keep the modem happy.  I normally suggest
that all modems be A.C. line powered, even if they do cost a bit more,
just to be safe (and to better assure long-term usefulness).

--Lauren--

ron%brl-bmd@sri-unix.UUCP (06/22/83)

From:      Ron Natalie <ron@brl-bmd>

What about the powered-by-the-rs232-signals modem Gandalf is now
putting out?  Doesn't sound too swift too me.

-Ron

BILLW%sri-kl@sri-unix.UUCP (06/23/83)

I dnt know, Seems to me that wit te newer CMOS chips, you
can do a lot with almost nil power...

BillW