Multi-Tech Systems MT2834MR6 manual Result Codes, Speed Conversion, MNP Error Correction

Chapter 5 - Error Correction, Data Compression, and Speed Conversion

5.11 Result Codes

When the MT2834MR6 connects with another modem with error-correction or data compression enabled, its CONNECT responses change to inform you of the type of connection. (See Appendix C for a complete list of result codes.)

5.11.1 MNP Error Correction

If terse responses are enabled, an R is added to the numeric code. If verbose responses are enabled, the word RELIABLE follows the CONNECT message.

5.11.2 LAP-M Error Correction

If terse responses are enabled, an L is added to the numeric code. If verbose responses are enabled, the word LAPM follows the CONNECT message.

5.11.3 Data Compression

If terse responses are enabled, a C is added to the numeric code. If verbose responses are enabled, the word COMPRESSED follows the CONNECT message.

5.12 Speed Conversion

Speed conversion allows the MT2834MR6 to communicate at one speed over the phone line, and at another speed at the RS-232 interface. The speed (baud rate) of the RS-232 interface, in bits per second (bps) can be fixed independently of the speed of the online transmissions.

Besides data compression, another popular application for speed conversion involves an autoanswer MT2834MR6 connected to a computer that does not have autobauding capability. This means that the computer must be set at a fixed baud rate, regardless of whether the modem is communicating over the phone line at 300, 1200, 2400, 4800, 9600, 14,400, 19,200, 21,600, 24,000, 26,400, or 28,800 bps. In this application, speed conversion allows the modem to match its speed to that of a calling modem, while at the same time communicating with the attached computer through its RS-232 serial port at a fixed baud rate, which can be preselected at 300, 1200, 2400, 4800, 9600, 19,200, 38,400, 57,600, or 115,200 bps.

The flow control and pacing methods used between the computer and the modem during speed conversion are the same as those used with V.42 error correction. The two choices (XON/XOFF or RTS/CTS) are selected by using the &E commands detailed earlier in this chapter. If you are not using the modem’s V.42 error correction, you must activate modem flow control with a separate command (&E11), as explained earlier.

There are three commands that relate specifically to speed conversion. They are the Baud Adjust ($BA), Modem Baud Rate ($MB) and Serial Port Baud Rate ($SB) commands.

75