Digicom COMSPHERE 3910 Installation And Operation Manual page 232

COMSPHERE 3900 Series Modems
Auxiliary Cables Not Supplied
To add an external telephone to your modem, use an external Y cable to connect the phone line
to both the modem and the telephone (Figure C-2).
Figure C-2. Wiring Diagram — Y Cable for External Telephone
C-4 September 1998 3910-A2-GN32-40