COMSPHERE 3900 Series Modems
1-4
September 1998
3910-A2-GN32-40
Carrier-Mounted Model 3911 4-Wire/2-Wire Modem
The carrier-mounted Model 3911 modem (Figure 1-2) is capable of either 4-wire/2-wire
leased-line or dial operation and installs into a COMSPHERE 3000 Series Carrier. The
Model 3911’s faceplate has 16 LED status indicators for displaying modem activity and an audio
speaker jack for the carrier’s optional speaker.
The Model 3911 modem’s rear has two edge card connectors that mount into a connector plate
located on the rear of the carrier. This connector plate has two DB-25-S connectors, one providing
an EIA-232-D DTE interface and one for future functionality.
FACEPLATE
496-14178b
EIA232/V.24
EDGE CARD
CONNECTOR
FUTURE
USE
BACK
CONNECTOR
PLATE
V
.35
(3600/3500)
RS366A/V
.25
(3800)
EIA232/V
.24
TXD
RXD
RTS
CTS
DSR
DTR
LSD
103
104
105
106
107
108
109
Pwr
Alrm
Test
Dial
RI
Busy
Serv
SQ
Status
Front Panel
3911
142
125
Spkr
EIA232/V.24
CONNECTOR
FUTURE
USE
GROUNDING
TAB
Figure 1-2. Model 3911
