Immediate Action Commands; Flow Control Commands - Multitech ISIHI-2S User Manual

Immediate Action Commands

Use immediate action commands to obtain information about AT commands and current modem settings.
A/ Repeat Last Command
Default: None
Type A/ to repeat the previous command. Do not precede this command with AT or press
ENTER to execute it.
In Information Request
n = 0
Default: none
This command displays specific product information about your modem.
I0 or I returns the controller firmware version number. Use this command to identify your
modem's firmware level before calling Multi-Tech Technical Support. (Same as I3.)
&Bn Dummy command
&V View Current Configuration
Default: none
Use the &V command to display the active modem settings.

Flow Control Commands

Flow control refers to techniques used by data terminal equipment and the modem to pause and resume the flow
of information between them. It prevents a device from accepting more data than it can handle. The modem
implements flow control in both directions. When the modem halts the flow of data, it is called flow control.
When the computer halts the flow, it is called pacing.
&Kn Local Flow Control Selection
n = 0, 3, or 4
Default: &K3
Allows you disable flow control and enable hardware or software flow control.
&K0 completely disables data flow control initiated by the modem. (Same as \Q0.)
&K3 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 \Q3.)
&K4 enables XON/XOFF software flow control. XON/XOFF flow control is an in-band
method of data flow regulation. In-band data regulation means that the XON (^Q) and XOFF
(^S) characters are inserted into the stream of data rather than using separate 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 \Q1.)
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
Chapter 5 - AT Commands
77