DCP Configuration
4-39
3920-A2-GN31-30
November 1996
Table 4-7
(7 of 8)
DTE Interface Configuration Options — Singleport Mode
A
Bakup_TXClk_Src: Internal
Nxt Internal External RXC_Loop
This configuration option only appears in customized installations in which the Dual_Leased_Ln is configured
for Enable and Async/Sync Mode is Sync.
Backup Transmit Clock Source. Selects the clock reference source when operating in the Dual Leased Line Mode. This
is a special mode in which one leased line is used to back up another.
Internal – The transmit data’s clock source is derived from the modem’s internal clock. This clock is available as an
output on Pin 15 (TXC) of the EIA-232-D interface.
External – The transmit data’s clock source is provided by the DTE on Pin 24 (XTXC) on the EIA-232-D interface.
Receive Clock Loop – The modem’s transmit clock is derived from its received analog signal. The derived clock is
available as an output on Pin 15 (TXC) of the EIA-232-D interface.
XTXC Clamps TXC: Enable
Nxt Enable Disable
This configuration option only appears when TX Clock Source is configured for External.
External Transmit Clock Clamps Transmit Clock. Allows the modem’s TXC output (Pin 15 on the EIA-232-D interface) to
be clamped OFF when TX Clock Source is configured for External.
Enable – TXC is clamped off when TX Clock Source is configured for External.
Disable – TXC continues to be provided when TX Clock Source is configured for External.
The AT command is S-Register S71=
n, where n is 0 for Enable and 1 for Disable.
CT111_Rate Cntl: Disable
Nxt Disable Fallback1 Fallback2
This configuration option does not appear when V.34 is enabled for a leased or dial line.
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.
Disable – Disregards CT111 Rate Control.
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.
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 when 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.
Disable – The data rate of the connection between the DTE and modem is the value of the Async DTE Rate
configuration option.
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.
