61182210L1-5A Issue 1, August 2003 5
NOTE
When the LTU is in T1 mode, all related E1
options will be non-applicable. A non-appli-
cable option setting is still changeable, but will
not take affect until the option become appli-
cable.
5. OPERATION
Test Capabilities
The Total Access SHDSL T1/E1 LTU has the following
test capabilities:
• Self diagnostics
• Local loopbacks
• EOC initiated remote loopbacks
• Internal bit error rate tester (BERT)
Self Diagnostics
The Total Access SHDSL T1/E1 LTU performs self
diagnostic tests of its Read Only Memory (ROM),
Random Access Memory (RAM), LEDs, and non-
volatile configuration setting upon power-up.
Local and Remote Loopbacks
For troubleshooting purposes, the SHDSL T1/E1 LTU
provides three types of loopback tests.
1. Dual sided
2. Network
3. Customer
BERT
The SHDSL T1/E1 LTU provides an internal bit error
rate tester (BERT) for the injection and observation of
random bit sequence to and from the SHDSL.
Customer Port
The SHDSL T1/E1 LTU operates in either E1 mode or
T1 mode.
E1 Mode
In E1 mode the port features are as follows:
• Carries information at the rate of 2.048 Mbps
• Uses CCS framed format with or without CRC-4
• Operates in either Alternate Mark Inversion (AMI)
or High-Density Bipolar 3 (HDB3) line code
• Provides programmable timeslot idle pattern
• Supports ISDN-PRA V3 service
• Displays additional status information via a local
VT100 management screen
See Table 5 for E1 port statistics definitions.
T1 Mode
In T1 mode the port features are as follows:
• Carries information at the rate of 1.544 Mbps
• Uses Superframe Format (SF) or Extended Super-
frame Format (ESF)
• Operates in either Alternate Mark Inversion (AMI)
or Bipolar w/8-Zero Substitution (B8ZS) line code
• Provides programmable timeslot idle pattern
• Monitors the Facility Data Link (FDL)
• Displays additional status information via a local
VT100 management screen
See Table 6 for T1 port statistics definitions.
NOTE
In T1 mode both the SHDSL T1/E1 LTU and
the SHDSL NTU must be operational.
