SI2457-D-FT Silicon Laboratories Inc, SI2457-D-FT Datasheet - Page 100

• Manufacturer Part Number: SI2457-D-FT
• Description: IC ISOMODEM SYSTEM-SIDE 24TSSOP
• Manufacturer: Silicon Laboratories Inc

Specifications of SI2457-D-FT

• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

AN93
Example: The United States specifies a busy tone “on” time from 450 to 550 ms and “off” time from 450 to 550 ms.
Thus the minimum “on” and “off” times are 0.45 s each , and the maximum “on” and “off” times are 0.55 s each.
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The hexadecimal values are stored in the appropriate registers using the AT:Uhh command. Detection parameters
can be wider than the minimum specifications. This is often done in the modem defaults and other suggested
settings so that one set of parameters can cover a broad number of different country requirements.
100
Minimum ON Time
BPF Biquad
The busy cadence minimum on time is 0.45 s, thus BMOT = 0.45 x 7200 = 0x0CA8.
The busy cadence minimum total time is 0.45 s + 0.45 s = 0.9 s, thus BMTT = 0.9 x 7200 = 6480 = 0x1950.
The maximum total time is 0.55 s + 0.55 s = 1.1 s, thus BDLT = (1.1 – 0.9) x 7200 = 1440 = 0x05A0.
Values
A0
B1
B2
A2
A1
K
K
(RMOT)
(BMOT)
Stage 1
0xC0F6
0x96AB
0x0020
0x7448
0x4000
—
—
Minimum Cadence
Table 50. BPF Biquad Values (Continued)
TOTAL Time
(BMTT)
(RMTT)
Maximum Cadence
Figure 26. Cadence Timing
0xC0CB
Stage 2
0x0200
0x7802
0x4000
0x8359
TOTAL Time
—
—
400/440
Rev. 1.3
Cadence Delta
Time (BDLT)
Stage 3
0xC2A4
(RDLT)
0x73D5
0x8D93
0x0400
0x4000
—
—
0xC26B
Stage 4
0x85C1
0x0040
0x75A7
0x4000
—
—
Output Scalar
0x0005
0x0008
—
—
—
—
—