Troubleshooting and Repair
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Loopback
Loopback is used to verify and locate the source of either a cable or
a synchronization problem through the devices in a T1 transmission
path. Devices in the T1 transmission path (PBX, CSU, Channel
bank, smart jacks, etc.) will generally have some type of loopback
mode. Loopback modes will typically have the effect of taking the
input T1 stream and transmitting the stream back to the source; the
nodes thereby verify that portion of the link.
In the absence of a loopback mode, the T1 transmits and receives
pairs that can be directly connected together to physically create a
loopback condition.
A&B bits
Taken from each of the 24 Channels to emulate the various analog
trunk signalling conditions (off-hook, on-hook, disconnect
supervision, etc.) in either of the two following methods.
Superframe:
Over a cycle of twelve frames, bits A&B are taken in
frames 6 & 12 to provide basic analog trunk emulation over the T1
facility.
Extended superframe (ESF):
ESF is not supported by the SX-200
EL/ML or the
SX-200 LIGHT. ESF is supported by an ISDN.
Refer to
Summary of Contents for SX-200 EL
Page 1: ...TECHNICIAN S HANDBOOK LIGHTWARE 19 RELEASE 3 0 ...
Page 11: ...Chapter 1 Introduction ...
Page 12: ......
Page 32: ...Technician s Handbook 22 ...
Page 33: ...Chapter 2 Routine Maintenance ...
Page 34: ......
Page 55: ...Chapter 3 Troubleshooting and Repair ...
Page 56: ...Technician s Handbook 46 ...
Page 88: ...Technician s Handbook 78 Figure 16 E M Trunk Type I 2 wire ...
Page 110: ...Technician s Handbook 100 ...
Page 111: ...Chapter 4 Programming ...
Page 112: ......
Page 168: ...Technician s Handbook 158 ...
Page 169: ...Chapter 5 Installation ...
Page 170: ......
Page 239: ...Chapter 6 Maintenance Commands ...
Page 240: ......
Page 258: ...Technician s Handbook 248 ...
Page 261: ...Notes ...
Page 262: ...Technician s Handbook Notes ...