DEC VAXstation 3100 Owner's Manual page 139

Use your modem documentation to clear the Force DSR
attribute on your modem. (By your clearing the Force DSR
attribute, your system will recognize the loss of modem
connection, should it occur.)
Attach the 25-pin D-sub adapter/DECconnect passive adapter
to the back of the modem.
Attach one end of the DEC 423 serial Hne cable to the 25-pin
D-sub/DECconnect adapter.
Attach the free end of the serial line cable to the
communications port on the back of the system unit, as
shown in Figure 8-2.
Figure 8-2 Connecting a Modenn to ttie System Unit
ri:
Modem Cable
MLO-002327
Adding Options ft-S