Telebit T3000 Reference Manual page 134

Possible contents for this register are as follows:
0 Disable automatic dialing.
1 Enable automatic dialing via an OFF to ON
transition on the DTR control signal line. When
DTR is ON, the modem goes off-hook and dials
the first or second number in the Number Directory
(the actual number is determined by the A/B
switch setting).
3 Enable automatic dialing from the front panel T/D
switch. When the modem is idle (OH indicator is
off), pressing the T/D switch causes the modem to
go off-hook and automatically dial the first or
second number in the Number Directory (the
actual number is determined by the A/B switch
setting).
4 When the DTR signal goes from OFF to ON, the
modem assumes the originate mode if the setting
of register 81 is equal to 0. If the setting of register
81 is greater than 0, the modem assumes the
answer mode.
For values 0 through 4, the S 100 register applies
unless it is overridden by an R dial modifier.
5105 T/D Switch Enable
Range: 0-2
Default: 1
The S 105 register enables or disables the T
ID
switch
on the front panel. Possible contents for this register
are as follows:
O
Disable the T/D switch.
1 Enable the T/D switch.
2 Enable the T/D switch only when the modem is on-
hook (OH indicator is off).
AT Register Descriptions 6-27