Silicon Laboratories SI2494/39, SI2493/57/34/15/04 manual Tip +

AN93

			Table 40. Extended AT& Command Set (Continued)
	Automatic determination of telephone line type.
	Result code: WXYZn
	W:	0	= line supports DTMF dialing.
		1 = line is pulse dial only.
	X:	0	= line supports 20 pps dialing.
&X1		1	= line supports 10 pps dialing only.
	Y:	0	= extension network present (PBX).
		1	= outside line (PSTN) connected directly.
	Z:	0	= continuous dial tone.
		1	= make-break dial tone.
	n:	0–9 (number required for outside line if Y = 0).1
&X2	Same as &X1, but Y result (PBX) is not tested.
Y2A2	Produce a constant answer tone (ITU-T) and return to command mode. The answer tone continues
	until the ATH command is received or the S7 timer expires.
&Z	Enter low-power wake-on-ring mode.

Notes:

1. The initial number attempted to test for an outside line is controlled by S51 (default = 1).

2. AT&$ reflects the last AT&P command issued but does not reflect any subsequent changes made by writing U registers with AT:U.

TIP +

600 Ω

Si3018 VTR

10 µF

RING –

Figure 25. Phone Line Termination Circuit

IL

Rev. 1.3 79