[. . . ] Communicator V. 34 Data/Fax Modem Plug n' Play PC Card Reference Guide (Document Part Number 61600-00005-003) Outline of Guide By Chapter 1. Using AT Commands Some Notes About AT Commands Configuring the Modem Sample Configuration Sample Configuration Sample Configuration AT Commands AT& Commands AT% Commands AT\ Commands AT) Commands AT* Commands AT: Commands AT- Commands AT+ Commands 2. S-Registers Example: Writing to an S-Register Bit-Mapped Options S-Registers Example: Setting an S-Register Example: Interpreting an S-Register Alphanumeric List of S-Registers 1. Using AT Commands Communications programs control your modem by issuing modem instructions called AT commands. [. . . ] This command reports a value which indicates the received signal level. Typical values are in the range from 0 to 2 and increase as the signal quality degrades. Based on this value, retrain or fallback/fall forward may be initiated if enabled by the %E1 or %E2 commands. The command reports an ERROR if the modem is not connected, or is connected at 300bps, V. 23, or fax modes. In V. 34, the symbol rate, SNR, THD, TX level and pre-emphasis are also reported. %L %Q AT\ Commands \An Maximum MNP Block Size Setting. In reliable mode, the modem will signal a BREAK through the active error correction protocol. In non-error correction mode, the modem will transmit a BREAK signal to the remote modem that is a length n times 100 ms, where n is between 1 and 9 (the default for n is 3). When the modem receives a break from the remote modem, the break is passed as follows: 1) For non-corrected modes, the break length is passed; 2) For error-corrected modes a 300mS break is passed. This command enables or disables software flow control between the local and remote modem. This command allows you to send a BREAK to stop data transfer without disconnecting. (See S40. ) The resulting behavior depends on the state of the modem: 1. Modem receives a BREAK from the computer while operating in data mode. \K1 Modem clears data buffers and sends BREAK to remote modem. \Bn \Gn \Kn \K2 Same as \K0. Modem receives a BREAK from the computer while operating in command mode. Modem receives BREAK from remote modem during non-error corrected connection: \K0 Clears data buffers and sends BREAK to computer. Modem receives BREAK from remote modem during reliable connection: the modem passes a 300 mS BREAK to the host. This command selects the error correction mode to be negotiated in subsequent connections. A normal connection is a connection with flow control, but no error correction or data compression. \N2 Selects a reliable connection (a connection that uses error correction). In this mode the modem will try to establish a V. 42 (LAPM) or MNP connection. (Equivalent to &Q5 S36=4 S48=7. ) \N3 Selects an auto-reliable connection. In this mode the modem will first try to establish a reliable connection. [. . . ] Default: 7 In Profile: Yes Writeable: Yes Bit Value Meaning 0, 1, 2 0 Modem disconnects if connection fails. 5 MNP connection is attempted and if it fails, a direct connection is established. 7 MNP connection is attempted and if it fails, a normal connection is established. (See also Nn. ) Range: 0-12, 15-21 Default: 0 In Profile: Yes Writeable: Yes 0 Automatic line speed detection ( 1 300 bps. [. . . ]