Datasheet

DS26518 8-Port T1/E1/J1 Transceiver
98 of 312
9.12.6.2 Local Loopback
The transmit system data is looped back to the receive framer. This data is also encoded and output on TTIPn and
TRINGn. Signals at RTIPn and RRINGn are ignored. This loopback is conceptually shown in
Figure 9-30.
Figure 9-30. Local Loopback
Line
Driver
Transmit
Framer
Optional
Jitter
A
ttenuator
Transmit
Digital
Transmit
A
nalog
TCLK
TSER
Receive
Framer
Optional
Jitter
A
ttenuator
Receive
Digital
Receive
A
nalog
RCLK
RSER
RTIP
RRING
TTIP
TRING
9.12.6.3 Remote Loopback 1
The outputs decoded from the receive LIU are looped back to the transmit LIU, not including the jitter attenuator in
the path. Remote Loopback 2 includes the jitter attenuator in the loopback path. The inputs from the transmit
framer are ignored during Remote Loopback 1.
9.12.6.4 Remote Loopback 2
The outputs decoded from the receive LIU are looped back to the transmit LIU, including the jitter attenuator. The
inputs from the transmit framer are ignored during Remote Loopback 2. This loopback is conceptually shown in
Figure 9-31.
Figure 9-31. Remote Loopback 2
Line
Driver
Transmit
Framer
Optional
Jitter
A
ttenuato
r
Transmit
Digital
Transmit
A
nalog
TCLK
TSER
Receive
Framer
Optional
Jitter
A
ttenuato
r
Receive
Digital
Receive
A
nalog
RCLK
RSER
RTIP
RRING
TTIP
TRING