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MDS Orbit MCR-4G Technical Manual
MDS 05-6628A01, Rev. B
Terminal Service
Understanding
The unit allows the setup of the COM ports as a terminal server that passes data to/from the serial
port to network interfaces. The serial port must be configured to do this, in addition to the baud rate
and data format. The data from the serial port is treated as a seamless stream; meaning it is not
protocol aware and will send data from the serial port to the remote endpoint as soon as the data is
received.
A terminal-server can consist of a TCP server, a TCP client, or a UDP endpoint, and a MODBUS-TCP
server.
When a terminal server on the unit is configured as TCP server, then the unit listens on a TCP port for
client connections. When a terminal server on the unit is configured as TCP client, then the unit will
attempt to connect to the remote IP address. Once a TCP connection is established, then serial traffic
from the COM port can pass to and from the TCP port as long as the TCP connection remains
established.
When a terminal server on the unit is configured as a UDP endpoint, then traffic from the COM port is
sent to the remote host at the specified port in UDP packets. Likewise, traffic sent to the UDP port of
the unit is forwarded out the COM port. Since UDP is stateless, some packets may not reach their
intended destination or may arrive out of order. The protocol contained in the UDP messages must
handle these scenarios.
NOTE:
Once a terminal-server is enabled on a COM port, the port stays in data mode and the CLI will
not be available on that port. To break out of data mode, the escape sequence
+++
can be entered
on the PC’s keyboard. The baud rate and format must match on the PC and on the unit for the
escape sequence to be detected. Once the sequence is detected, the login prompt is presented as
long as the port is enabled for console access.
Configuring
The following shows how to enable a UDP terminal server on COM1
admin@(none) 01:34:45% set services serial terminal-server server COM1 mode udp port 10000
remote address 192.168.1.12 port 10000
[ok][2012-06-19 01:35:36]
[edit]
admin@(none) 01:35:36% commit
The following shows how to enable a TCP terminal server on COM1
admin@(none) 01:22:09% set services serial terminal-server server COM1 mode tcp-server port 30011
idle-timeout 30
[ok][2012-06-19 01:22:36]
[edit]
admin@(none) 01:22:36% commit
