User`s guide

Protocols
Modem 3600 6-3
Direct Mode
The DTE speed and DCE speed are forced to be the same. No error
control or buffering.
Note
In direct mode, with the DCE link established at a rate other
than the original DTE speed, the modem issues the connect
message for the new DTE speed at the original rate. All
subsequent data will be sent to the DTE at the new DCE
speed.
Flow Control
If the serial port speed exceeds that of the modem connection,
characters may be sent by the DTE to the modem faster than it can send
them to the remote modem. The modem holds characters in an internal
buffer until they can be transmitted. When this buffer is full, the modem
uses flow control to cause the DTE to stop sending characters. As the
modem continues to transmit data and the buffer empties, flow control is
again used to cause the DTE to resume sending data. The modem can
use hardware flow control (RTS/CTS) or in-band flow control (XON/
XOFF).
Protocol Commands
These commands enable or control the various data compression, flow
control, and error correction options of the modem. Tabl e6-1 lists the
features associated with each mode.
Note
Bold text indicates command parameter defaults.