Introduction to the RFC-2217 COM Port Control Protocol
NetModem & NetSerial supports an enhancment to
the telnet protocol known as "COM Port Control"
COM Port Control increases compatibility between Access
Servers and many PC applications.
In order for COM Port Control to work, both ends of
the telnet connection (the server and client) need to
support it. Many Access Server Manufactures support
COM Port Control, including Cisco, Digi, Comtrol, and
What is "COM Port Control"?
"COM Port Control" is an extension of the
Telnet Protocol. It allows NetModem & NetSerial to send configuration
information to the Access Server. If also allows the
Access Server to send NetModem & NetSerial any status changes (Connect
status). It also allows NetModem & NetSerial to manage flow control
with the Access Server.
When making a connection with out using "COM Port
Control", NetModem & NetSerial is able to interact
by sending and receiving data.
COM Port Control Protocol Features Available in NetModem
& NetSerial, The COM Port Control protocol includes
a number of features.
NetModem & NetSerial uses the COM Port protocol to provide the
following port controls:
DTR signal, Data Terminal Ready used to disconnect a
NetModem & NetSerial uses the COM Port protocol
to report the following conditions:
DCD, Data Carrier Detect
DSR, Data Set Ready
RI, Ring Indicator