Telnet Com Port Control Option (RFC2217)
Original Publication Date: 1997-Oct-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
This memo proposes a protocol to allow greater use of modems attached to a network for outbound dialing purposes. This memo defines an Experimental Protocol for the Internet community.
Network Working Group G. Clark Request for Comments: 2217 Cisco Systems, Inc. Category: Experimental October 1997
Telnet Com Port Control Option
Status of this Memo
This memo defines an Experimental Protocol for the Internet community. This memo does not specify an Internet standard of any kind. Discussion and suggestions for improvement are requested. Distribution of this memo is unlimited.
This memo proposes a protocol to allow greater use of modems attached to a network for outbound dialing purposes.
Table of Contents 1. Negotiation of the Com Port Control Option Protocol .................. 5 2. Com Port Configuration Commands .................. 6 Version Baud Rate Data Bit Size Parity Stop Bit size 3. Special Com Port Control Commands ................. 8 XON/XOFF Flow Control HARDWARE Flow Control BREAK Signal DTR Signal RTS Signal 4. Notification of Com Port and .................. 12 Modem Line Changes 5. Flow Control .................. 13 6. Security Considerations .................. 13 7. Author’s Address .................. 14 8. Reference Section .................. 14
The Telnet protocol defines an interactive, character-oriented communications session. It was originally designed to establish a session between a client and a remote login service running on a host .
Clark Experimental [Page 1]
RFC 2217 Telnet Com Port Control Option October 1997
Many new business functions require a person to connect to remote services to retrieve or deposit information. By in large, these remote services are accessed via an async dial up connection. This new class of functions include:
- dial up connections to the Internet - connecting to bulletin boards - connecting to internal and external databases - sending and receiving faxes.
The general nature of this new class of function requires an interactive, character-oriented communications session via an async modem. This is typically known as outbound modem dialing.
To help defer the cost of installing and maintaining additional phone lines which may be used very little per person, many equipment manufacturers have added the ability to establish a Telnet session directly to the outbound ports on many of the most popular access servers and routers, here after referred to as access servers.
However, the current Telnet protocol definitions are not sufficient to fully support this new use. There are three new areas of functionality which need to be added to the Telnet protocol to successfully support the needs of outbound modem dialing. These are:
- The ability for the client to send com port configuration information to the access server which is connected to the outbound modem. This is needed to ensure the data being transmitted and received by the modem is formatted correctly at the byte level.
- The ability for the access server to inform the client of any modem line or signal changes such as RLSD changes (carrier detect). This information is vital, since many client software...