Guardian Technologies DFT 150/175 7.4Modem Operation, Dial=, Modem dial string, default, ATDT

DVST Installation GuideModems

DIAL=	Modem dial string
	(default, ATDT)
	This is the command that must precede all numbers that the MODEM
	has to dial. Typically the MODEM will dial using either pulse or tone
	dialling. This is dependent on the telephone exchange the MODEM is
	connected to, most modern exchanges are able to accept tone dialling
	which is faster than the older pulse dialling method.
	For tone dialling: DIAL=ATDT
	For pulse dialling: DIAL=ATDP

Tip: Extra information can be linked to the above commands, internal exchanges that require a “9" to be dialled to access outside lines can have this added to the dial string, typically ATDT9.

7.4Modem Operation

All modern modems respond to a set of “Hayes” commands. There are several differences in these commands from manufacturer to manufacturer. It is important to use the correct commands with each modem and not to attempt to use one manufacturer’s set up with another manufacturer’s modem.

If possible modems should be linked to DVST in the synchronous mode. Some modems, for example those using PEP (Packet Ensemble Protocol), can only be used in the asynchronous mode.

Cables for connection to synchronous and asynchronous modems are different and are not interchangeable. Refer to the Cable Assemblies chapter for further details.

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