Rainbow Electronics DS26519 - Manual (Page 258)

DS26519 16-Port T1/E1/J1 Transceiver
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Register Name: LRISMR
Register Description: LIU Receive Impedance and Sensitivity Monitor Register
Register Address: 1007h + (20h x (n - 1)) + (2000h x [(n - 1) / 8]): where n = 1 to 16
Bit
# 7 6 5 4 3 2 1 0
Name REXTON RIMPON — — — RIMPM2 RIMPM1 RIMPM0
Default 0 0 0 0 0 0 0 0
Bit 7: Receive External Resistor On (REXTON)
0 = RTIPn and RTIPEn are not connected (high impedance to the line) (if RIMPON is disabled).
1 = RTIPn and RTIPEn are connected.
Bit 6: Receive Internal Impedance Match On (RIMPON)
0 = Receive internal impedance termination is disabled (high impedance).
1 = Receive internal impedance termination is enabled.
Bits 2 to 0: Receive Impedance Selection (RIMPM[2:0]). These bits are used to select the receive impedance
termination. They must be set according to the cable impedance even if internal termination resistance is disabled
(RIMPON = 0). See
Table 10-22 .
Note: For the DS26519, fully internal termination is not supported (package power dissipation issue).
Table 10-22. Receive Impedance Selection
RIMPON RIMPRM[2:0] RECEIVE IMPEDANCE SELECTED (
Ω)
0 x00 75
Ω external termination (no internal impedance match)
0 x01 100
Ω external termination (no internal impedance match)
0 x10 110
Ω external termination (no internal impedance match)
0 x11 120
Ω external termination (no internal impedance match)
1 000 75
Ω, with external 120Ω resistor
1 001 100
Ω, with external 120Ω resistor
1 010 110
Ω, with external 120Ω resistor
1 011 120
Ω, with external 120Ω resistor
1 100 Reserved
1 101 Reserved
1 110 Reserved
1 111 Reserved