ADC ICX-250 - Manual (Page 58)

Testing ICX-250 Diagnostics 55
Issue 1, September 1998 ADCP-62-023
© 1998, ADC Telecommunications, Inc.
T1 Loopback
T1 Network
ICX-250
Transmit Receive
FRAMER
LIU
CPU
CPE Device
Network or Remote Loopback
11277-A
T1 Network
ICX-250
Transmit Receive
Transmit Receive Transmit Receive
FRAMER
LIU
CPU
CPE Device
Local Loopback
The incoming T1 signal is looped
inside the T1 Framer and returned to
the T1 Network. This exercises the
T1 Line Interface Unit and the T1
Framer with the exception of the
HDLC controller and clock switching
circuitry. The outgoing T1 signal is looped
inside the T1 LIU and returned to the
CPE Device. This exercises the T1
Line Interface Unit, the T1 Framer,
CPU, Data Port Interface, and the
FXS Interface with the exception of
the HDLC controller. The data ports
can be exercised up to full T1 rate.