ds26524 Maxim Integrated Products, Inc., ds26524 Datasheet - Page 82

• Manufacturer Part Number: ds26524
• Description: Ds26524 Quad T1/e1/j1 Transceiver
• Manufacturer: Maxim Integrated Products, Inc.

8.11.5 LIU Loopbacks
The DS26524 provides four LIU loopbacks for diagnostic purposes: analog loopback, local loopback, remote
loopback, and dual loopback. In the loopback diagrams that follow, TSER, TCLK, RSER, and RCLK are
inputs/outputs from the framer. Note that the framer input/output can be in IBO mode where a single TSER/RSER
can be shared by up to eight framers.
8.11.5.1
The analog output of the transmitter TTIP and TRING is looped back to RTIP and RRING of the receiver. Data at
RTIP and RRING is ignored in analog loopback. This is shown in
Figure 8-16. Analog Loopback
8.11.5.2
The transmit system data (the internal signals TPOS, TNEG, and TCLK) is looped back to receive-side inputs to
the receive jitter attenuator. The data is also output on TTIP and TRING. Signals at RTIP and RRING are ignored.
This loopback is conceptually shown in
Figure 8-17. Local Loopback
TSER
TCLK
RSER
RCLK
TCLK
TSER
RCLK
RSER
TRANSMIT
RECEIVE
FRAMER
FRAMER
Analog Loopback
Local Loopback
TRANSMIT
FRAMER
RECEIVE
FRAMER
ATTENUATOR
ATTENUATOR
OPTIONAL
OPTIONAL
JITTER
JITTER
ATTENUATOR
ATTENUATOR
OPTIONAL
OPTIONAL
Figure
JITTER
JITTER
8-17.
TRANSMIT
DIGITAL
82 of 273
RECEIVE
DIGITAL
TRANSMIT
DIGITAL
RECEIVE
DIGITAL
TRANSMIT
ANALOG
TRANSMIT
RECEIVE
ANALOG
ANALOG
RECEIVE
ANALOG
Figure
8-16.
LINE
DRIVER
LINE
DRIVER
RRING
RTIP
TRING
TTIP
RTIP
RRING