Telenetics 326X V.34, V.34-SDC, V.32bis Series manual Flow Control

Quick-Reference

Configuration

Table A-1.

AT Commands, Cross-Referenced to Front Panel Options (Continued)

AT	Parameter &
Command	Option	Description
AT*FC2	=Lvl2	Lvl2 applies to V.32 (coded or uncoded)/V.32bis modulation modes only. It includes the Lvl1
		function and shortens training time by approximately 2 seconds.
AT*FC3	=Lvl3	Lvl3 includes the Lvl1 and Lvl2 function and eliminates error-correction negotiation, saving
		approximately an additional half second. For proper operation, enable this option and ensure
		that AT*SM (Mode), AT*EC (Error Correction), and AT*DC (Data Compression) (EC/DC
		OPT’S category) are set the same in both modems.
		NOTE: Selecting Lvl3 in the V.34 modulation mode bypasses error correction negotiation and
		improves the connect time of the modems as described above.
		If your local and remote modems are configured for SDC operation by selecting Fast Call Lvl3,
		the modems use LAPM error correction with V.42bis data compression only. For proper
		operation, enable this option in both modems, and ensure that the AT*SM (Mode) is set the
		same in both modems.
	Flow	Flow Control
		Allows the modems and DTEs in a link to control the flow of data when buffers near their
		capacity. Use some type of flow control when operating in the Normal or Reliable mode.
		Check the DTE’s manual to ensure that the DTE supports the type of flow control you select.
AT*FL0	=Off	Flow control is disabled.
AT*FLl	=XON/XOFF	The local modem and DTE operate flow control by passing characters embedded in the data
		stream between them. The XOFF character signals the transmitting device to stop sending data.
		The XON character lets the halted device start sending data. NOTE: XON/XOFF flow control
		is not supported in SDC mode.
AT*FL2	=DTR/CTS	In asynchronous applications, the local modem and DTE use DTR/CTS signals to operate flow
		control.
		In SDC applications, DTR/CTS flow control operates the same as asynchronous applications,
		except flow control is unidirectional from the local modem to the DTE through the CTS signal;
		the modem uses CTS to signal when the buffers are full. The DTR signal has no impact on flow
		control in synchronous applications.
AT*FL3	=RTS/CTS	In asynchronous applications, the local modem and DTE use RTS/CTS signals to operate flow
		control. The terminal uses RTS to signal when its buffers are full. The modem uses CTS to
		signal when its buffers are full. An on-to-off transition signals the transmitting device to stop
		sending data; an off-to-on transition signals that data can flow.
		In SDC applications, RTS/CTS flow control functions the same as asynchronous applications,
		except flow control is unidirectional from the local modem to the DTE through the CTS signal;
		the modem uses CTS to signal when the buffers are full. The RTS signal has no impact on flow
		control in synchronous applications.
AT*FL4	=XON/XOFF PT	XON/XOFF Pass-Through Flow Control. The local modem and DTE operate flow control by
		passing characters embedded in the data stream between them. Check your DTE manual to
		verify if the DTE recognizes XON/XOFF flow control.

NOTES:

1)Pass-through flow control must be used with caution when Mode=Normal and Modem Flow=On because XON/XOFF characters are acted on by the remote modem at its DCE port.

2)Pass-through flow control is not applicable in 326X-SDCmode. If SDC is enabled, and you select XON/XOFF PT, the modem operates as if flow control were disabled.

Gray shading indicates country-specific options. See Appendix C for your country’s options.

A-20 Configuration Quick Reference