DataComm V.34 PL, Operation Manual

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Operation Operating Procedures
3-8 DataComm V.34 PL Modem 060R115-000
Installation and Operation Issue 1
The following DTE data rates are available when the modem operates in V.13 synchronous or
asynchronous mode:
Real/Constant Carrier Mode [CA.r]
In Real/Constant Carrier mode - (select
CA.r
from the front panel) With constant (continuous)
carrier, the modem’s transmitter is always ready to transmit signals at the data input lead. Carrier
stays on independent of RTS from the terminal. It can be used for both synchronous and
asynchronous data.
The following DTE data rates are available when the modem operates in Real/Constant
synchronous or asynchronous mode:
Clock Selection
The synchronous format relies on transmit and receive clocks to maintain character timing. It
therefore does not need start and stop bits for each character as does the asynchronous format. The
DataComm V.34 PL modem can be configured to use one of the following three clock sources to
transmit synchronous data:
• Internal - transmit clock generated by the DataComm V.34 PL modem.
• External - transmit clock signal generated by the DTE is passed to the modem along with data.
• Receiver - transmit clock derived by the local modem from the data it is receiving from the
remote modem (also called wrap timing).
The preferred clock source varies for different computer systems. Consult your computer's manual
for its particular specifications.
Regardless of which transmit clock source it is using, the DataComm V.34 PL modem always
outputs its transmit clock signal to the DTE on pin 15 of the EIA interface. Pin 17 always provides
the receive clock signal derived from the incoming data. When the DTE provides external transmit
clock it does so on Pin 24.
9600 bps (enter 96)
4800 bps (enter 48)
2400 bps (enter 24)
9600 bps (enter 96)
4800 bps (enter 48)
2400 bps (enter 24)
Note The receive clock is always controlled by the remote modem that sends the data being received.
It is not recommended to have the local and remote modems both configured to derive transmit
clock from received data.