Motorola V3229 Operating Instructions - Page 209

8 Protocols When a LAPM or MNP link is established the modem is in reliable mode. V.42 bis allows negotiation with a remote modem to the highest level of protocol common to both units. Both LAPM and MNP control data errors by retransmitting any block of data that was corrupted in transit. LAPM is assigned highest priority and if not supported, then an MNP connection is attempted. AUTO-RELIABLE In auto-reliable mode the modem negotiates to the highest protocol (LAPM or MNP) common to both modems. However, if a reliable connection cannot be established, auto-reliable allows the protocol to fallback to normal mode. CONSTANT SPEED INTERFACE The modem serial port adapts to the data rate of the DTE and does not change speed if the modem telephone line connects at another speed. Therefore the DTE to DCE interface speed is constant. DATA COMPRESSION Using MNP Class 5 data compression, the modem can achieve data throughput approaching 28800 bps. With LAPM data compression, the modem can achieve data throughput approaching 57600 bps. This increase in speed is achieved by automatically analyzing the data stream and reducing the number of bits required to represent the characters. 100% error-free transmission is assured by the application of the MNP or LAPM error control protocol on the compressed data. Compression takes place only if the modem detects -2 V.3229 / V.3229L