Rainbow Electronics DS3170 User Manual
Page 136
DS3170 DS3/E3 Single-Chip Transceiver
136 of 233
0 = TXP and TXN driven
1 = TXP and TXN tri-stated
Bit 13: Receive LIU Monitor Mode (RMON) This bit is used to enable the receive LIU monitor mode pre-amplifier.
Enabling the pre-amplifier adds about 20 dB of linear amplification for use in monitor applications where the signal
has been reduced 20 dB using resistive attenuator circuits.
0 = Disable the 20 dB pre-amp
1 = Enable the 20 dB pre-amp
Bit 12: Transmit LIU LBO (TLBO) This bit is used enable the transmit LBO circuit which causes the transmit
signal to have a wave shape that approximates about 225 feet of cable. This is used to reduce near end crosstalk
when the cable lengths are short. This signal is only valid in DS3 LIU mode.
0 = TXP and TXN have full amplitude signals
1 = TXP and TXN signals approximate 225 feet of cable
Bits 10 to 8 : Port Interface Mode (LM[2:0]). The LM[2:0] bits select main port interface operational modes. The
default state disables the LIU and the JA.
Table 9-26. Line Mode Select Bits LM[2:0]
LINE.RCR
.RZSD
(PORT.CR2)
Line Code
LIU
JA
0 000
B3ZS/HDB3
OFF
OFF
0 001
B3ZS/HDB3
ON
OFF
0 010
B3ZS/HDB3
ON
TX
0 011
B3ZS/HDB3
ON
RX
1 000
AMI
OFF
OFF
1 001
AMI
ON
OFF
1 010
AMI
ON
TX
1 011
AMI
ON
RX
X 1XX
UNI
Bits 5 to 3: Framing mode (FM[2:0]). The FM[2:0] bits select main framing operational modes. Default: DS3 C-
bit.