Silicon Laboratories SI2493/57/34/15/04 manual Dial Registers, Line Interface/Control Registers

AN93

Table 92. Dial Registers

Register	Value	Function
	Pulse Dial Control
U37–U40		Pulse per Digit Definition
U42	PDBT	Pulse Dial Break Time
U43	PDMT	Pulse Dial Make Time
U45	PDIT	Pulse Dial Interdigit Time

DTMF Control

U46	DTPL	DTMF Power Level (and
		Twist)
U47	DTNT	DTMF On Time
U48	DTFT	DTMF Off Time

Table 93. Line Interface/Control Registers

Register	Bit	Value	Function
U4D	10	CLPD	Check Loop Current Before
			Dialing
	1	LLC	Low Loop Current Detect
			(set for legacy TBR21)
	0	LCN	Loop Current Needed
U50		LCDN	Loop Current Debounce
			On Time
U51		LCDF	Loop Current Debounce
			Off Time
U52		XMTL	Transmit Level
U67:	7	DCR	DC Impedance Select
13:12	6	OHS	On-Hook Speed
MINI
	3:2	DCV	DC Termination Select
9 ILIM
	1	RZ	Ringer Impedance
	0	RT	Ringer Threshold Select
U68	2	BTE	Billing Tone Protect Enable
	1	ROV	Receive Overload
	0	BTD	Billing Tone Detected

6.2.2.3. Special Requirements for India

To output a 0 dBm sine wave, use the following commands:

AT:PF800, C4DD, 7B5C, 595F

AT*Y254:W50, 0, 5B86,1

AT:U46,0

AT*Y1X1DT1

This command string turns off the high-frequency DTMF tone, leaving only the low-frequency DTMF tone when an ATDT is sent. The tone is output continuously until any key is pressed. To restart the tone output, type AT*Y1DT1. To change the tone power level, type ATU46,00X0 (where X is a hexadecimal value 0–F representing output power in –1 dBm steps from 0 to –15 dBm).

146 Rev. 1.3