Datasheet

____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
311 of 366
Register Name:
LRISMR
Register Description:
LIU Receive Impedance and Sensitivity Monitor Register
Register Address:
base address + 0x1C
Bit # 7 6 5 4 3 2 1 0
Name RG703 RIMPON RIMPM2 RIMPM1 RIMPM0 RMONEN RSMS1 RSMS0
Default 0 0 0 0 0 0 0 0
Bit 7: Receive G.703 Clock (RG703).
Setting this bit to 1 configures the LIU to receive the 2048kHz
synchronization signal described in G.703 section 13 on RTIP/RRING.
Bit 6:
Receive Impedance On (RIMPON).
See section 10.13.3.1.
0 = Disable internal impedance match (termination) for the receiver
1 =
Enable internal impedance match (termination) for the receiver
Bit 5 to 3: Receive Impedance Match (RIMPM[2:0]). These bits are used to select the receive impedance match
(i.e. termination) value. These bits must be set to match the cable impedance. Even if the internal impedance is
turned
off (RIMPON=0), the external cable impedance must be specified in this field for proper operation. See
section 10.13.3.1.
RIMPM[
2:0]
RECEIVE IMPEDANCE SELECTED (
)
000
External 120
 resistor parallel with internal impedance to make 75 termination
001
External 120
 resistor parallel with internal impedance to make 100 termination
010
External 120
 resistor parallel with internal impedance to make 110 termination
011
External 120
 and no internal impedance
100
75
 internal termination
101
100
 internal termination
110
110
 internal termination
111
120
 internal termination
Bit 2: Receiver Monitor Mode Enable (RMONEN). See section 10.13.3.4.
0 = Di
sable receive monitor mode.
1 = Enable receive monitor mode. Resistive gain is added with the maximum sensitivity. The receiver
sensitivity is determined by RSMS[1:0] below.
Bit 1, 0: Receiver Sensitivity / Monitor Gain Select 1, 0 (RSMS[1:0]).
These bits are used to select the receiver
sensitivity level and additional gain in monitoring applications. The monitor mode bit (RMONEN above) adds
resistive gain to compensate for the signal loss caused by the isolation resistors. See sections 10.13.3.2.
Monitor Mod
e Disabled (RMONEN=0)
RSMS[1:0]
RECEIVER MONITOR
MODE GAIN (dB)
RECEIVER SENSITIVITY
(MAX CABLE LOSS ALLOWED) (dB)
00 0 12
01 0 18
10 0 30
11 0 36 for T1; 43 for E1
Monitor Mode Enabled (RMONEN=1)
RSMS[1:0]
RECEIVER MONITOR
MODE GAIN (dB)
RECEIVER SENSITIVITY
(MAX CABLE LOSS ALLOWED) (dB)
00 14 30
01 20 22.5
10 26 17.5
11 32 12