Installation guide

What Is Modem Emulation?
Chapter 3 Modem Emulation Commands 151
This chapter describes the commands that can be issued when Digi
devices are configured in modem emulation mode.
What Is Modem Emulation?
Modem emulation enables a system administrator to configure a
networked Digi device to act as a modem. The Digi device emulates
modem responses to a serial device and seamlessly sends and receives
data over an Ethernet network instead of a PSTN (Public Switched
Telephone Network). The advantage for a user is the ability to retain legacy
software applications without modification and use a less expensive
Ethernet network in place of public telephone lines.
As an aid in configuring modem emulation, the Digi Device Setup Wizard
and the default web interface have a serial port profile for modem
emulation.
Modem Emulation Cable Signals
Use the following signal assignments to make a cable connecting the Digi
device to a serial device.
DSR and DTR on the serial device side are connected to the DSR signal of
the Digi device.
Modes of Operation
There are two modes of operation in modem emulation:
• Command mode: Issuing AT commands to a Digi device.
• Data mode: After a network connection is established, the device
switches to data mode.
Chapter 3
Modem Emulation Commands