COMSPHERE 3900 Series Modems
5-18
September 1998
3910-A2-GN32-40
Table 5-1
(9 of 10)
DTE Interface Configuration Options
CT111_Rate Cntl: Disable
Nxt Disable Fallback1 Fallback2
CT111 Rate Control. Allows the DTE to control modem rate via Pin 23 of the EIA-232-D interface. This
configuration option determines the effect of the DTE Rate control signal. CT111 is also known as CH on
the EIA-232-D interface.
H
Disable
Disregards CT111 Rate Control.
H
Fallback1
Forces the modem to decrease its configured data rate to the next lower data rate when CT111 is
OFF. Valid only for V.32bis, V.33, V.29 modulation. Modem will only fall back within the same
modulation scheme. When CT111 turns ON, the modem returns to its previous data rate.
H
Fallback2 (Not available for TMp tributaries)
Forces the modem to decrease two data rates while remaining in the same modulation scheme.
When CT111 turns ON, the modem returns to its previous data rate.
NOTE: This configuration option is only valid in Async Direct mode and Synchronous mode. For proper
operation, disable the V.32bis Autorate and V.32bis Automode configuration options.
The AT command is S-Register S61=n, where n is 0 for Disable, 1 for Fallback1, and 2 for Fallback2.
DTE_Rate=VF: Disable
End Disable Enable
This configuration option does not appear if Async/Sync is configured for Sync.
DTE Rate = VF. Forces the DTE’s data rate to be equal to the VF (telephone line) data rate.
H
Disable
The data rate of the connection between the DTE and modem is the value of the Async DTE Rate
configuration option.
H
Enable
The data rate between the DTE and modem is the same as the modem’s VF data rate. As a
result, when the modem is in Data mode, the speed of the data passed between the modem and
DTE occurs at the VF data rate.
The AT command is S-Register S90=n, where n is 0 for Disable and 1 for Enable.
