I've got a US Robotics Sportster 128k ISDN terminal adapter with the
external ring generator. The ISDN side works fine. (64kbps is so nice.)
However the external ring generator doesn't seem to generate enough "ring"
(voltage? current?) to trigger my analog (POTS) answering machine when it's
the only thing hooked up. Let alone when anything else is also hooked up.
I desperately need to find / build something to get my answering machine
working. Does any body know of a product, kit, book, Elmer, something that
I could use to solve this problem?
Thanks for any info.
Tom Sayles
KE4HET
Equipment specs:
ISDN TA
USR Sportster 128k
"U" interface
http://www.usr.com/home/isdnspec.html
RJ-11 type connector
pin 3 ring
pin 4 tip
Analog Phone Interface
AC impedance 600 ohms 20%
DC source resistance 600 ohms 5%
Loop current 35mA max
Loop voltage 25Vdc max
Answering Machine
DuoFone TAD-345
model no: 43-7008
ringer equivalence 0.8B
External Ring Generator
small black box
2 foot long six conductor cord w/ RJ-11 plug
four conductor RJ-11 jack
no documentation or specifications other than
plug into Analog Phone Interface of USR Sportster 128k and
plug phone into External Ring Generator