Multi-Tech MultiModem ISIHI-2S, Manual

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80 MultiModemISI Hybrid Series, ISIHI-2S
Chapter 4—MODEM AT Commands, S-Registers, Result Codes
Modem
control lines. When an XOFF character is detected, the data stream is suspended until
an XON character is detected. If you issue the &K4 command to the modem, it will
respond to XON/XOFF pacing, and use XON/XOFF characters as its own method of flow
control to the computer. (This is the same as &K4.)
The drawback to using this method of pacing is that some files may contain these
characters as part of the file data. If such a file is transferred using a modem with XON/
XOFF flow control enabled, the file transfer could fail due to indefinite suspension.
\Q3 enables modem’s use of Clear to Send (CTS) signal on the RS-232/V.24 interface to
regulate data flow. When CTS drops, data flow is suspended until the signal goes
high
(on) again. This method of flow control works in conjunction with pacing (i.e., computer-
initiated flow control), which uses the Request to Send (RTS) signal on the RS-232/V.24
interface. Hardware flow control cannot be enabled unless an active error correction
protocol is selected. This is the factory default setting. (This is the same as &K3.)
\X n XON/XOFF Pass-Through
n = 0
Default: \X0
When XON/XOFF pacing is active, the local modem has two options regarding the XON
and XOFF characters. It can respond to and discard the characters from the computer, or
it can respond to the characters and pass them through the data communications link to
the remote modem, thereby pacing the remote modem as well.
&X0 causes the modem to respond to and discard the XON and XOFF characters. This
is the default.
&J n Auxiliary Relay Control
n = 0
Default: &J0
The &J0 command causes the auxiliary relay to remain open. It is never closed. This is
the default, and the only supported command format.
\G n Modem Port Flow Control
n = 0
Default: \G0
This command returns an OK for backward compatibility with some software.
\J n Data Buffer Control
n = 0
Default: \J0
This command enables data buffer control. Serial port speed is independent of connect
speed.
\J0 enables data buffer control. This is the default, and the only supported command
format.