Black Box 3600 manual Auto-Reliable Mode, Constant Speed Interface, Data Compression, Normal Mode

Protocols

Auto-Reliable Mode

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 DCE-to-DCE data link 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 33600 bps. With LAPM data compression, the modem can achieve data throughput approaching 115200 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 that the remote modem supports compression. If not, a reliable connection is made without compression.

Although data compression is compatible with any type of data, it is most efficient for ASCII text files. For maximum throughput when using data compression, the terminal should be set to a higher speed than the connect speed with the constant speed interface on and flow control enabled. When transmitting or receiving data files in one direction, the throughput can be increased for V.42 bis by having extra buffer and more processor time with the %C2 and %C3 data compression commands.

Normal Mode

No error control, with or without constant speed DTE interface. Data is buffered.

6-2 Modem 3600