8: Channel Mode: Channel Configuration
XPress™ DR Industrial Device Server User Guide
52
Modem (Emulation) Mode:
In Modem Mode, the unit presents a modem interface to the
attached serial device. It accepts AT-style modem commands, and handles the modem signals
correctly.
Normally there is a modem connected to a local PC and a modem connected to a remote
machine. A user must dial from the local PC to the remote machine, accumulating phone charges
for each connection. Modem Mode allows you to replace modems with device servers, and to use
an Ethernet connection instead of a phone call, without having to change communications
applications and make potentially expensive phone calls.
To select Modem Mode, set the Connect Mode to
C6
(no echo),
D6
(echo with full verbose), or
D7
(echo with 1-character response).
Note:
If the unit is in Modem Mode and the serial port is idle, the unit can still accept network
TCP connections to the serial port if Connect Mode is set to C6 (no echo), D6 (echo with full
verbose), or D7 (echo with 1-character response).
In Modem Mode, echo refers to the echo of all of the characters entered in command mode; it
does not mean to echo data that is transferred. Quiet Mode (no echo) refers to the modem not
sending an answer to the commands received (or displaying what was typed).
To disconnect a connection using Modem Mode commands:
There must be 1-second guardtime (no data traffic) before s++.
There must not be a break longer that 1 second bs.
There must be another 1-second guardtime after the last + is sent.
The unit acknowledges with an
OK
to indicate that it is in command mode.
Enter
ATH
and press
Enter
. It is echoed if echo is enabled. ATH is acknowledged by another
OK
.
Table 8-7 Modem Mode Commands
Modem Mode
Command
Function
ATDTx.x.x.x,pppp or
ATDTx.x.x.x/pppp
Makes a connection to an IP address (x.x.x.x) and a remote port number
(pppp).
ATDTx.x.x.x
Makes a connection to an IP address (x.x.x.x) and the remote port number
defined within the unit.
ATD0.0.0.0
Forces the unit into monitor mode if a remote IP address and port number
are defined within the unit.
ATD
Forces the unit into monitor mode if a remote IP address and port number
are not defined within the unit.
ATDx.x.x.x
Makes a connection to an IP address (x.x.x.x) and the remote port number
defined within the unit.
ATH
Hangs up the connection (Entered as +++ATH ).
ATS0=n
Enables or disables connections from the network going to the serial
port.
n=0 disables the ability to make a connection from the network to the serial
port.
n=1-9 enables the ability to make a connection from the network
to the serial port.
n>1-9 is invalid.
ATEn
Enables or disables character echo and responses.
n=0 disables character echo and responses.
n=1 enables character echo and responses.
