User`s guide

70 Chapter 8 Special Features: Modem Emulation
ATDT ipaddress:tcp_port#
an example is ATDT 146.135.13.5:50001
Answering Calls
The Digi device listens on a pre-defined TCP port to receive data. When
the Digi device receives a call notification (RING) through a serial port to
begin a TCP connection, it needs to reply with an ATA or a pre-configured
Auto-Answer to answer the call.
Note: The TCP ports assigned to the serial ports are as follows:
Serial port 1 listens on TCP port 50001
Serial port 2 listens on TCP port 50002
Serial port 3 listens on TCP port 50003
Serial port 4 listens on TCP port 50004
Disconnecting Calls
The TCP connection disconnects by either dropping the DTR signal on the
serial port or sending the escape sequence <P>+++<P> to the Digi device.
<P> represents a one second pause.
Disconnecting Calls-Digi Device
The Digi device sends a NO CARRIER response to the serial port when
the network connection is dropped.
Modem Emulation AT Command Set
AT
Command
Function
Result
Code
ATA
Answer command: The Digi device will go off hook and answer a TCP
connection request.