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4 61223441L1-5C
Description T200 H4R Installation and Maintenance Practice
In an effort to minimize this down time, the Fast Retrain feature has been implemented. If an impairment (bad
splice, for example) causes the HDSL data pump to lose frame synchronization for 500 msec or longer, instead of
retraining, a fast retrain will be attempted. This abbreviated train can achieve data mode in 5 to 7 seconds. A
successful fast retrain should be evident by watching the Span Status screen and by reduced unavailable seconds
(UAS) in the PM data for each LOS alarm recorded.
NOTE
Fast-Retrain capable units must be installed on both ends of the HDSL4 circuit for
this feature to function properly. Also, if there is a failure of a fast retrain attempt,
for any reason, then the traditional (25-30 second) retrain will be initiated.
Compatibility
The T200 H4R is used in conjunction with any T1.418 compliant span powering H4TU-C and an H4TU-R.
Compatible ADTRAN HDSL4 transceiver units are listed in Table 1.
Due to span power limits, the number of H4Rs permitted in the circuit depends upon the type of H4TU-C utilized.
An ADTRAN T200 H4R provides DS1 transport on all revised resistance design (RRD) 26 AWG and/or 24 AWG
loops. Three ADTRAN T200 H4R repeaters may be added to extend the range of a loop.
Repeater placement is determined by the following criteria:
• On single H4R loops, only on the attenuation properties of the loop segment must be considered.
• For a circuit requiring two H4Rs, both segment attenuation as well as segment DC resistance requirements be
satisfied.
• For a circuit requiring three H4Rs, H4TU-C and H4TU-R hardware requirements, segment attenuation, and
segment DC resistance requirements must all be satisfied.
Refer to the “HDSL4 Deployment Guidelines” section of this practice and the deployed H4TU-C.
Table 1. ADTRAN Unit Compatibility
Part Number Unit Name
118141xLy Total Access 3000 H4TU-C
122x401Ly 220 H4TU-C
122x403Ly DDM+ H4TU-C
122x404Ly 3192 H4TU-C
122x407Ly Soneplex H4TU-C
122x424Ly T200 H4TU-R, Local Power
122x426Ly T200 H4TU-R, Span Power
x = any generic number; y = any list number