Specifications

Si2457/Si2434/Si2415
Rev. 0.91 51
Reset settings = 0x0008
U67 ITC1
BitD15D14D13D12D11D10D9D8D7D6D5D4D3D2D1D0
Name MINI[1:0] ILIM DCR OHS DCV[1:0] RZ RT
Type R/W R/W R/W R/W R/W R/W R/W
Bit Name Function
15:14 Reserved Read returns zero.
13:12 MINI[1:0] Minimum Operational Loop Current.
Adjusts the minimum loop current at which the DAA can operate. Increasing the minimum oper-
ational loop current can improve signal headroom at a lower TIP/RING voltage.
MINI[1:0] Min Loop Current
00 10 mA
01 12 mA
10 14 mA
11 16 mA
11:10 Reserved Read returns zero
9ILIMCurrent Limiting Enable.
0 = Current limiting mode disabled.
1 = Current limiting mode enabled. This mode limits loop current to a maximum of 60 mA per
the TBR21 standard.
8 Reserved Read returns zero.
7 DCR DC Impedance Selection.
0 = Normal dc impedance. This mode should be used for all standard
applications.
1 = 800 Ω dc termination.
6OHS
On-Hook Speed.
This bit works in combination with the OHS2 bit (U62, bit 8) to set the on-hook speed. The on-
hook speeds are measured from the time the OH bit is cleared until loop current equals zero.
OHS OHS2 Mean On-Hook Speed
0 0 Less than 0.5 ms
0 1 3 ms ±10% (meets ETSI standard)
1 X 26 ms ±10% (meets Australia spark quenching spec)
5:4 Reserved Read returns zero.
3:2 DCV[1:0] TIP/RING Voltage Adjust.
These bits adjust the voltage on the DCT pin of the line-side device, which affects the TIP/RING
voltage on the line. Low voltage countries should use a lower TIP/RING voltage. Raising the
TIP/RING voltage can improve signal headroom.
DCV[1:0] DCT Pin Voltage
00 3.1 V
01 3.2 V
10 3.35 V
11 3.5 V