Specifications

Si2457/Si2434/Si2415

42 Rev. 0.91

U17 BT1A0 BT1 registers set the coefficients for stage 1 of the Busy Tone Detect filter.

Default is for FCC countries. See “AN93: Modem Designer’s Guide” for other

country settings.

0x0800

U18 BT1B1 0x0000

U19 BT1B2 0x0000

U1A BT1A2 0x0000

U1B BT1A1 0x0000

U1C BT2A0 Busy tone detect filter stage 2 biquad coefficients. 0x00A0

U1D BT2B1 0x6EF1

U1E BT2B2 0xC4F4

U1F BT2A2 0xC000

U20 BT2A1 0x0000

U21 BT3A0 Busy tone detect filter stage 3 biquad coefficients. 0x00A0

U22 BT3B1 0x78B0

U23 BT3B2 0xC305

U24 BT3A2 0x4000

U25 BT3A1 0xB50A

U26 BT4A0 Busy tone detect filter stage 4 biquad coefficients. 0x0400

U27 BT4B1 0x70D2

U28 BT4B2 0xC830

U29 BT4A2 0x4000

U2A BT4A1 0x80E2

U2B BTK Busy tone detect filter output scaler. 0x0009

U2C BTON Busy tone detect ON threshold. 0x00A0

U2D BTOF Busy tone detect OFF threshold. 0x0070

U2E BMTT Busy cadence minimum total time in seconds multiplied by 7200.

See “AN93: Modem Designer’s Guide” for details.

0x0870

U2F BDLT Busy cadence delta in seconds multiplied by 7200. 0x25F8

U30 BMOT Busy cadence minimum on time in seconds multiplied by 7200. 0x0438

U31 RMTT Ringback cadence minimum total time in seconds multiplied by 7200. 0x4650

U32 RDLT Ringback cadence delta in seconds multiplied by 7200. 0xEF10

Table 15. U-Register Description (Continued)