k9un@iwsl7.UUCP (07/28/83)
I have a Rixon Sangamo 1200b modem that worked fine 'til I moved to a new office here at the labs. On my new data line, I can dial my phone, get an answer and carrieer, but the modem refuses to recognize it (all the usual signals like TR.. are ok). The modem works fine on other lines. The line "seems" to function fine audibly. I also tried a DEC DFO3 modem and it also doesn't work. Finally, I tried a Penril DCD modem and what da ya know? It works! Any suggestions? Our local people who are in charge of these lines have no t been very responsive. I seem to remeb=mber having a similar problem at home on my apple with the Rixon modem. Wes Ague
w8sdz@brl@sri-unix.UUCP (07/29/83)
From: Keith Petersen <w8sdz@brl> Make sure that only "tip" and "ring" are connected at the modular plug. (that's usually red and green wires). If the other two (usually unused) black and yellow wires are connected, some modems will refuse to operate. Because of this, some manufacturers of modems are suppling a modular "Y" connector that only supports tip and ring connections to the modem. In a commercial multi-line telephone the yellow and black wires are used for what's called the "A Lead", which is a circuit that connects to auxilary hook-switch contacts in your telephone. This circuit is used to cancel the "Hold" relay when you pick up the phone. --Keith
rb@houxn.UUCP (R.BOTWIN) (07/29/83)
Most likely problem is polarity! Try reversing the tip and ring wires (usually red/green pair)... All other things being equal that seems to be the problem... Some things are polarity sensitive (like older touchtone units). Rob Botwin ABI/BTL .....houxn!rb
BILLW%sri-kl@sri-unix.UUCP (07/29/83)
Also, when you have a second line installed many places, they just use the "unused" yellow and black wires for the second line. The normal phone signals present on the remaining two wire are definately capable of preventing a modem from working properly, as I have determined on two seperate occasions with Vadic triple modems... BillW