ATCommands

Leased Line Operations

A leased line, or private line, is a telephone line that permanently connects two or more locations. The leased line does not have any switching equipment associated with it.

Leased-line operation with the modem is selected with the &L command.

The &L command informs your modem that communications will occur over leased lines, with no answer tones being generated by the modem. If the modem detects a loss of the remote carrier signal while leased-line operation is selected, it will attempt to re-establish the connection rather than hang up.

If you select leased line operation with the &L1 command, you must issue the ATA command to answer a call, and the ATD command to initiate a call. If you use &L2 or &L3 to select Auto leased line operation, you do not need to issue the ATA or ATD commands; &L2 selects Originate mode automatically and &L3 selects Answer mode automatically. To dial or answer, raise DTR; to return to local command state, lower DTR.

You will require a special phone cable (available from your dealer) to connect your modem to a leased-line socket. The phone cable supplied with your modem is suitable for use with normal, dial-up, voice (PSTN) lines.

Before commencing leased-line communications, it is recommended that a non-auto-ranging B setting be specified.

If error correction is required, select a Reliable mode, not an Auto- Reliable mode. (See the \N command.)

Auto-ranging and fallback are disabled in leased-line mode. Your modem will only attempt to connect using the communications standard specified by the B command and the terminal speed.

Once a connection has been established, if your modem detects a loss of carrier it will continuously attempt to re-establish the connection.

Smart Leased- Line Mode

Leased-line operation is available in both asynchronous and synchronous modeÊ 1.

Calling and AnsweringUsing &L1

When operating in smart mode (&L1 set), the ATD and ATA commands are used to initiate and answer calls respectively.

Page 53

Page 53
Image 53
Telenetics 56 manual Leased Line Operations, Smart Leased- Line Mode, Calling and AnsweringUsing &L1