Perle Systems Perle IOLAN DS1 - Manual (Page 99)

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Serial Port Profiles
Virtual Modem Profile
Overview
Virtual Modem (Vmodem) is a feature of the IOLAN that provides a modem interface to a serial
device. It will respond to AT commands and provide signals in the same way that a serially attached
modem would. This feature is typically used when you are replacing dial-up modems with the
IOLAN in order to provide Ethernet network connectivity.
Functionality
The serial port will behave in exactly the same fashion as it would if it were connected to a modem.
Using AT commands, it can configure the modem and the issue a dial-out request (ATTD). The
IOLAN will then translate the dial request into a TCP connection and data will be begin to flow in
both directions. The connection can be terminated by ’hanging’ up the phone line.
You can also manually start a connection by typing ATD<ip_address>,<port_number> and end
the connection by typing +++ATH . The ip_address can be in IPv4 or IPv6 formats and is the IP
address of the receiver. For example, ATD123.34.23.43,10001 or you can use
ATD12303402304310001 , without any punctuation (although you do need to add zeros where there
are not three digits presents, so that the IP address is 12 digits long).