Specifications

AN93
Rev. 0.9 79
3.3.15. 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 37). 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.
3.3.16. U34–U35 (Dial Tone Timing)
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 38).
3.3.17. U37–U45 (Pulse Dial Registers)
Registers U37–U40 set the number of pulses to dial
digits 0 through 9, respectively (see Table 39). 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 "3.5.20. Country Dependent Setup" on page 138.
U42, U43, and U45 set the pulse dial break-time
(PDBT), make-time (PDMT), and inter-digit delay time
(PDIT), respectively. The values are entered in
hexadecimal format and represent ms units. The default
values meet FCC requirements. The default dialing
speed is 10 pps. See "3.5.20. Country Dependent
Setup" on page 138 for Japanese 20 pps dialing
configuration.
Table 37. 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
Table 38. 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