Introduction to the RFC-2217 COM Port Control Protocol

NetModem & NetSerial supports an enhancment to the telnet protocol known as "COM Port Control" IETF RFC-2217. 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 Lantronix.

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:

Baud rate
Data Length
Parity bit
Stop bits
Example: 9600,N,8,1
DTR signal, Data Terminal Ready used to disconnect a call

NetModem & NetSerial uses the COM Port protocol to report the following conditions:

DCD, Data Carrier Detect
DSR, Data Set Ready
RI, Ring Indicator