Paradyne 3800PLUS manual of V.42/MNP/Buffer Configuration Options

Configure Branch

V.42/MNP/Buffer

V.42/MNP/Buffer configuration options determine the type of error correction and flow control used by the modems and attached DTEs.

Some choices within this group may not appear depending upon how previous configuration options have been selected. If the Async/Sync Mode configuration option is set for synchronous operation (see DTE Interface configuration options group), then the V.42/MNP/Buffer group does not appear on the LCD. Any changes made to configuration options within this group only take effect after a disconnect.

Table 8-6 shows each V.42/MNP/Buffer configuration option as it appears on the LCD, with the Async Dial factory default setting (the default value if the modem is just being installed) shown following the colon (:) on the first line and with all available selections listed on the second line. Following this is a description of the configuration option, a description of the available selections, and any equivalent AT commands.

Table 8-6

(1 of 6)

V.42/MNP/Buffer Configuration Options

*Err Contrl Mode: V42/MNPorBfr

Nxt V42/MNPorBfr V42/MNPorDsc MNP_or_Buffr MNP_or_Disc BufferMode DirectMode

LAPM_or_Disc LAPM_or_Buffr

Determines the type of error control used by the modem. In most cases, V42/MNPorBfr is the best choice. If V.42bis and MNP are enabled, then the modem uses the following priority for error control negotiation: V.42, MNP 5 and below, and Buffer Mode. Online changes do not take effect until a disconnect occurs.

V.42/MNP or Buffer ± Modem attempts to connect in V.42 Error Control mode. If this fails, the modem attempts to connect in MNP mode. If this fails, the modem connects in Buffer mode and continues operation. This is also known as V42/MNP Autoreliable Mode.

V.42/MNP or Disconnect ± Modem attempts to connect in V.42 Error Control mode. If this fails, the modem attempts to connect in MNP mode. If this fails, the modem disconnects. This is also known as Reliable mode.

MNP or Buffer ± Modem attempts to connect in MNP mode. If this fails, the modem connects in Buffer mode. This is also known as MNP Autoreliable Mode.

MNP or Disconnect ± Modem attempts to connect in MNP mode. If this fails, the modem disconnects. This is also known as Reliable mode.

Buffer Mode ± Modem does not use error control and allows the DTE rate to differ from the communications line rate. This mode should only be used if the DTE provides its own error control or if errors in data can be tolerated. This setting is also known as Normal mode and is valid even if the remote modem is set for Direct mode.

Direct Mode ± Modem connects at a data rate equal to or less than the initial DTE interface rate. (The modem never connects at a data rate greater than the initial DTE rate.) If the modem connects at a data rate lower than the DTE rate, the DTE must then adjust its data rate to equal the modem rate. Ultimately, the modem speed and DTE speed must be the same. Direct mode does not support error control or data buffering.

LAPM or Disconnect ± Modem attempts to connect in V.42 Link Access Procedure for Modems (LAPM) error control mode. If this fails, the modem disconnects. This setting should be used for cellular connections (at both the mobile and PSTN sides) when it is known that both sides support V.42.

LAPM or Buffer ± Modem attempts to connect in V.42 LAPM error control mode. If this fails, the modem connects in Buffer mode and continues operation.

NOTE: The modem must be reconfigured for Direct mode before changing the leased-line modulation if V.42 error control or Buffer mode are enabled with V.32bis on leased lines.

For Async Dial and UNIX Dial, V42/MNPorBfr is the factory default.

For Sync Dial and Sync Leased, DirectMode is the factory default.

AT command equivalent is \Nn.

*This configuration option is only available if Async/Sync Mode is configured for Async. Refer to the DTE Interface configuration options group for more on Async/Sync Mode.

3980-A2-GB30-20 November 1996 8-31