Silicon Laboratories SI2494/39 manual Ringback Cadence Registers, Dial Tone Timing Register

AN93

5.7.4. U31–U33 (Ringback Cadence Registers)

U31, U32, and U33 set the ringback cadence minimum total time (RMTT), ringback cadence delta time (RDLT), and ringback cadence minimum on time (RMOT) (see Table 51). Country-specific settings for ringback cadences are specified as a range for “on” time (minimum “on” and maximum “on”) and a range for “off” time (minimum “off” and maximum “off”). The three values represented by RMTT, RDLT, and RMOT fully specify these ranges. RMTT, minimum total time, is equal to the minimum “on” time plus the minimum “off” time. RDLT (allowable delta) is equal to the maximum total time (maximum “on” time plus the maximum “off” time) minus the minimum total time (RMTT). RMOT is the minimum “on” time. The values stored in the registers are the hexadecimal representation of the times in seconds multiplied by 7200. Default values meet FCC requirements.

Table 51. Ringback Cadence Registers

Register	Name	Description	Default
U31	RMTT	Ringback cadence minimum total time in seconds multiplied by 7200.	0x4650
U32	RDLT	Ringback cadence delta in seconds multiplied by 7200.	0xEF10
U33	RMOT	Ringback cadence minimum on time in seconds multiplied by 7200.	0x1200

5.7.5. U34–U35 (Dial Tone Timing Register)

U34 determines the period of time the modem attempts to detect a dial tone. U35 sets the time within this window that the dial tone must be present in order to return a valid dial tone detection. The value stored in U35 is the hexadecimal representation of the time in seconds multiplied by 7200.

The value in U34 is the hexadecimal representation of the time in seconds multiplied by 1000. The time window represented in U34 must be larger than the dial tone present time represented in register U35 (see Table 52).

Table 52. Dial Tone Timing Register

Register	Name	Description	Default
U34	DTWD	Window to look for dial tone in seconds multiplied by 1000	0x1B58
U35	DMOT	Minimum dial tone on time in seconds multiplied by 7200	0x2D00

5.7.6. U37–U45 (Pulse Dial Registers)

Registers U37–U40 set the number of pulses to dial digits 0 through 9, respectively (see Table 53). The values are entered in hexadecimal format with digit 0 having a default setting of 0x000A (10 decimal) pulses, digit 1 having a default setting of one pulse, digit 2 having a default setting of two pulses, etc. This pulse arrangement is used throughout most of the world. There are, however, two exceptions—New Zealand and Sweden. New Zealand requires 10 pulses for 0, nine pulses for 1, eight pulses for 2, etc. Sweden, on the other hand, requires one pulse for 0, two pulses for 1, etc. Complete information is provided in "6.2. Country-Dependent Setup" on page 133.

U42, U43, and U45 set the pulse dial break time (PDBT), make time (PDMT), and interdigit delay time (PDIT), respectively. The values are entered in hexadecimal format and represent milliseconds. The default values meet FCC requirements. The default dialing speed is 10 pps. See "6.2. Country-Dependent Setup" on page 133 for Japanese 20 pps dialing configuration.

Rev. 1.3 101