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MODEM 32144
This option controls the DTE
speed; however, it is effective only
when the modem is operating in
V.42 mode, MNP mode or buffer
mode. (If the modem is not in one
of these modes, the DTE speed will
be the same as the connect rate.)
The DTE speed can be set for
38.4, 19.2, or 115.2 Kbps or 9600,
4800, 2400, 1800, 1200, 600, 300,
or 110 bps (except that 1800 bps
is not available if the modem is
in Hayes mode). The default
DTE speed is 38.4 Kbps.
DTE speed refers to the speed of
data transfer between the DTE and
the local modem—it is not
necessarily the same as the data
transmission speed between the
connected modems. If flow control
is disabled, the DTE speed must be
equal to or less than the modem
speed, and the local and remote
DTE speeds must be equal.
For Hayes mode operation, this
option sets the default DTE speed
that will be effective after powerup
or after a full modem reset.
However, the default DTE speed is
automatically overridden when the
modem is autobauded (when an
"AT" attention code is sent to the
modem).
52
Flow Control
The flow control options control
the data flow according to the
availability of memory in the
buffer. Flow control can be set
independently for the terminal
to the modem (DTE-DCE) and for
the modem to the terminal (DCE-
DTE). The flow control options
include DTE-DCE, DCE-DTE and
Pass-through Flow Control.
Note the following:
• Flow control only applies to
asynchronous connections with
V.42 error correction or buffer
mode enabled.
• When flow control is disabled,
the DTE data rate must be
equal to or less than the
modem data rate, and the local
and remote DTE data rates
must be equal. (This precludes
the need for flow control—
which some DTE devices
cannot handle—and avoids
buffer overflow.)
• For DTE-DCE and DCE-DTE
Flow Control options: When
RTS on/off or CTS on/off flow
control is used and a buffer
connection has been
established, conditions that
will stop the data flow (e.g.,
dropped RTS) should not be
permitted for long periods,
if possible, to reduce the
possibility of buffer overflow.
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