Dial Command Modifiers

Command modifiers define additional parameters to the modem that instruct the modem to perform certain functions automatically when dialing a phone number. They are only valid when they are contained in a dial string (that follows the D command). The commands that are used to accomplish this task are called dial modifiers, and are placed in the dial string prior to issuing the command.

Syntax: ATD{dial modifier} 1234567 [Enter]

Basic dial modifiers are:

• P -- Pulse dialing. Also known as rotary dialing, this dial modifier follows the D command and precedes the telephone number to tell the modem to dial the number using pulse service.
• T -- Tone dialing. This modifier selects the tone method of dialing using DTMF tones. Note: Tone and pulse dialing can also be combined in a dial command line when both dialing methods are required.
• ; -- Resume command mode after dialing. If you need to dial a number that is too long to be contained in the command buffer (45 characters for the D command), use the (;) modifier to separate the dial string into multiple dial commands. All but the last command must be end with the ; modifier.
• , -- Pause While Dialing. The comma (,) dial modifier causes the modem to pause while dialing. The modem will pause the number of seconds specified in S-Register S8 and then continue dialing. If a pause time longer than the value in S-Register S8, it can be increased by either inserting more than one (,) in the dial command line or changing the value of S-Register S8. In the following example, the command accesses the outside (public) telephone line with the 9 dial modifier. Because the comma (,) dial modifier is present, the modem delays before dialing the telephone number 5551212. Ex: ATD 9, 5551212 [Enter]
• ! -- Using the Hook Flash. The exclamation mark (!) dial modifier causes the modem to go on-hook (hang up) for one-half second and is equivalent to holding down the switch-hook on your telephone for one-half second. This feature is useful when transferring calls.
• W -- Wait for a Subsequent Dial Tone. The W dial modifier causes a modem to wait for an additional dial tone before dialing the numbers that follow the W. The length of time the modem waits depends on the value in S-Register S7. The modem can be instructed to dial through PBXs (Private Branch Exchanges) or long-distance calling services that require delays during dialing. This can be done with the W command to wait for a secondary dial tone or with a comma (,) command to pause for a fixed time and then dial. Ex: ATDT 9 W 1 2155551212 [Enter]

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