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# B.3. Backslash and Percent Commands

Table B-3. Backslash and Percent Commands

Command | Description | Comments
--- | --- | ---
\A0 or \A | Character maximum MNP block size | 64 character maximum
\A1 | Character maximum MNP block size | 128 character maximum
\A2 | Character maximum MNP block size | 192 character maximum
\A3 | Character maximum MNP block size | 256 character maximum
%C0 or %C | Data Compression Enable/Disable | Disabled
%C1 | Data Compression Enable/Disable | MNP5 enabled
%C2 | Data Compression Enable/Disable | V.42bis (BTLZ) Enabled
%C3 | Data Compression Enable/Disable | MNP5 & V.42bis (BTLZ) Enabled
%D0 or %D | Data compression | 512 BLTZ dictionary size
%D1 | Data compression | 1024 BLTZ dictionary size
%D2 | Data compression | 2048 BLTZ dictionary size
%D3 | Data compression | 4096 BLTZ dictionary size
%E0 or %E1 | Escape method | ESCAPE DISABLED
%E1 | Escape method | +++AT method (default)
%E2 | Escape method | `Break` AT method
%E3 | Escape method | BOTH methods enabled
%E4 | Escape method | Disable `OK` to +++
%E5 | Escape method | Enable `OK` to +++
\J0 or \J | DTE Auto Rate Adjustment | Disabled
\J1 | DTE Auto Rate Adjustment | DTE rate is adjusted to match carrier rate.
\N0 or \N | Connection type | Normal connection (see below for definitions)
\N1 | Connection type | Direction connection
\N2 | Connection type | MNP Auto-reliable connection
\N3 | Connection type | Auto-reliable connection
\N4 | Connection type | V.42bis reliable link with phase detection
\N5 | Connection type | V.42bis auto-reliable link with phase detection
\N6 | Connection type | V.42 reliable link with phase detection
\N7 | Connection type | V.42 auto-reliable link with phase detection

A direct connection is a simple straight-through connection without any error connection or data compression. In this case, the computer-to-modem and modem-to-modem speeds must be identical.

A normal connection uses flow control (either software or hardware) to buffer the data being sent or received, so that the modem can transmit data at a different rate than the computer is actually sending or receiving it. For example, a computer may send actual data at 57kbps, but using compression, the modem only actually sends 28.8kbps. This is the mode use by most modems.

A reliable connection is a type of normal connection; if, for some reason, data compression or error correction cannot be established or maintained, the connection will hang up. (In essence, such a modem ensures that all connections are reliable, for it will hang up if the connection isn't.)

Likewise, an auto-reliable connection is virtually the same, except that the modem will try to renegotiate the connection in order to establish a reliable connection. Again, this is the mode that most modems use.

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