si2401 Silicon Laboratories, si2401 Datasheet - Page 65

• Manufacturer Part Number: si2401
• Description: V.22bis Isomodem With Integrated Global Daa
• Manufacturer: Silicon Laboratories

SF5 (DAA5). DAA Low Level Functions 5
Reset settings = 0000_0000 (0x00)
Bit
7:6
5:4
Name
3
2
1
0
Type
Bit
Reserved
Reserved
OHS[1:0]
Name
ILIM
RZ
RT
D7
Read returns zero.
On-Hook Speed.
These bits set the amount of time for the line-side device to go on-hook. The on-hook
speeds specified are measured from the time the register is written until loop current
equals zero.
OHS[1:0]
Current 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.
Ringer Impedance.
0 = Maximum (high) ringer impedance.
1 = Synthesized ringer impedance used to satisfy a maximum ringer impedance specifi-
cation in countries, such as Poland, South Africa, and Slovenia.
Do not modify.
Ringer Threshold Select.
Used to satisfy country requirements on ring detection. Signals below the lower level do
not generate a ring detection; Signals above the upper level are guaranteed to generated
a ring detection.
0 = 13.5 to 16.5 V
1 = 19.35 to 23.65 V
00
01
1X
D6
D5
Mean On-Hook Speed
Less than 0.5 ms
3 ms ±10% (Meets ETSI standard)
20 ms ±10% (Meets Australian spark quenching spec)
RMS
OHS[1:0]
RMS
R/W
Rev. 1.0
D4
Function
ILIM
R/W
D3
R/W
RZ
D2
D1
Si2401
R/W
RT
D0
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