Datasheet

DS26521 Single T1/E1/J1 Transceiver
78 of 258
8.11.5.3 Remote Loopback
The outputs decoded from the receive LIU are looped back to the transmit LIU. The inputs from the transmit framer
are ignored during a remote loopback. This loopback is conceptually shown in
Figure 8-24.
Figure 8-24. Remote Loopback
LINE
DRIVER
TRANSMIT
FRAMER
TRANSMIT
ANALOG
TCLK
TSER
OPTIONAL
JITTER
ATTENUATOR
RCLK
RSER
RTIP
RRING
TTIP
TRING
RECEIVE
ANALOG
RECEIVE
DIGITAL
TRANSMIT
DIGITAL
OPTIONAL
JITTER
ATTENUATOR
RECEIVE
FRAMER
LINE
DRIVER
TRANSMIT
FRAMER
OPTIONAL JITTER
ATTENUATOR
TRANSMIT
DIGITAL
TRANSMIT
ANALOG
TCLK
TSER
RECEIVE
FRAMER
OPTIONAL JITTER
ATTENUATOR
RECEIVE
DIGITAL
RECEIVE
ANALOG
RCLK
RSER
RTIP
RRING
TTIP
TRING
8.11.5.4 Dual Loopback
The inputs decoded from the receive LIU are looped back to the transmit LIU. The inputs from the transmit framer
are looped back to the receiver with the optional jitter attenuator. This loopback is invoked if RLB and LLB are both
set in the LIU Maintenance Control register (
LMCR). This loopback is conceptually shown in Figure 8-25.
Figure 8-25. Dual Loopback
LINE
DRIVER
TRANSMIT
FRAMER
OPTIONAL
JITTER
ATTENUATOR
TRANSMIT
DIGITAL
TRANSMIT
ANALOG
TCLK
TSER
RECEIVE
FRAMER
OPTIONAL
JITTER
ATTENUATOR
RECEIVE
DIGITAL
RECEIVE
ANALOG
RCLK
RSER
RTIP
RRING
TTIP
TRING