Datasheet

DS26521 Single T1/E1/J1 Transceiver
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Register Name:
LRISMR
Register Description:
LIU Receive Impedance and Sensitivity Monitor Register
Register Address:
1007h
Bit # 7 6 5 4 3 2 1 0
Name RG703 RIMPOFF RIMPM1 RIMPM0 RTR RMONEN RSMS1 RSMS0
Default 0 0 0 0 0 0 0 0
Bit 7: Receive G.703 Clock Enable (RG703).
If this bit is set, the receiver expects a 2.048MHz or 1.544MHz
clock from the RTIP/RRING, based on the selection of T1 (1.544) or E1 (2.048) mode in the
LTRCR register.
Bit 6: Receive Impedance Termination Off (RIMPOFF).
0 =
Receive terminating impedance match is enabled.
1 =
Receive terminating impedance match is disabled.
Bits 5 and 4: Receive Impedance Match 1 and 0 (RIMPM[1:0]).These bits are used to select the receive
impedance match value. These must be set according to the cable impedance. Even if the internal receive match
impedance is turned
off (RIMPOFF); the external cable impedance must be specified for optimum operation by
RIMPM1 to 0. See
Table 9-18.
Bit 3: Receiver Turns Ratio (RTR).
0 = Receive transformer turns ratio is 1:1.
1 = Receive transformer turns ratio is 2:1. This option should only be used in short-haul applications.
Bit 2: Receiver Monitor Mode Enable (RMONEN).
0 = Disable receive monitor mode.
1 = Enable receive monitor mode. Resistive gain is added with the maximum sensitivity. The receiver
sensitivity is determined by RSMS1 and RSMS0.
Bits 1 and 0: Receiver Sensitivity/Monitor Gain Select 1 and 0 (RSMS[1:0]).
These bits are used to select the
receiver sensitivity level and additional gain in monitoring applications. The monitor mode (RMONEN) adds
resistive gain to compensate for the signal loss caused by the isolation resistors. See
Table 9-19 and Table 9-20.
Table 9-18. Receive Impedance Selection
RIMPM[1:0]
RECEIVE IMPEDANCE
SELECTED (Ω)
00 75
01 100
10 110
11 120