Intel 537EX manual Voice I/O Primitive Codes, Relay/Playback Control, Primitive Code Description

IS-101 Voice Mode AT Commands

Table 25. Voice Mode Command Descriptions (Continued)

Command Default	Description
	Relay/Playback Control: (cont.)

		Voice I/O Primitive Codes
			Primitive Code	Description
			L	Local phone
+VLS=m	0		T	Telco line
(cont.)			M0	Internal microphone
			M1	External microphone
			S0	Internal speaker (requires squelch on any microphone activity)
			S1	External speaker (requires squelch on any microphone activity)
			H0	External microphone and speaker combination (handset or headset)
		NOTE: For speakerphone applications, see ATI10, +VSP, and “Speakerphone AT Command
			Requirements” in the Voice Application Note for more details.
		Automatic Hang-Up Control: This command changes the way the modem responds to hang-up
		commands after it switches from voice mode to fax or data modes.
		Range: 0–2
+VNH=m	0	0*	The modem retains automatic hang-ups as normal in data and fax modes
		1	The modem disables automatic hang-ups usually found in non-voice modes
		2	The modem disables all automatic hang-ups usually found in non-voice modes except a
			‘logical’ hang-up
		Ringback-Goes-Away Timer: After originating a call in voice mode, this command selects the length
		of time the DCE waits between ringbacks before the DCE assumes the remote party has gone off
		hook. After dialing a phone number and detecting a ringback, the modem sends <DLE><O> to the DTE
		if another ringback is not detected within this timer value. This indicates that the remote telephone has
+VRA=m	50	been picked up (that is, gone off-hook). The ringback-goes-away timer is reset every time a new
		ringback is detected.
		Range: 0–50 (in 100 ms increments)
		0	The DCE returns the ‘OK’ code immediately after ringback.
		50*	(50 = 5.0 seconds)*
		Ringback-Never-Appeared Timer: This command sets the length of time the DCE waits for ringback
		when originating a call in voice mode. After dialing a phone number, the modem sends an ‘Error’ result
		code to the DTE if ringback is not detected before the timer value elapses. This may indicate one of
		several conditions: the remote telephone was picked up before the ringback tone was generated; the
+VRN=m	10	number is no longer in service; or the number was incomplete. This timer is disabled after detecting the
		first ringback.
		Range: 0–255 (in 1 second increments)
		0	The DCE immediately returns the OK result code after dialing
		10*	(10 = 10 seconds)*

NOTE: An asterisk (*) denotes the factory-default setting.

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