HDSL4 for General Distribution Installation and Maintenance Practice HDSL4 Deployment Guidelines61223HDSL4L2-5C 55HDSL4 DEPLOYMENT GUIDELINESThe different segments of an HDSL4 circuit are defined in Figure 52.Figure 52. HDSL4 Circuit SegmentsNOTEFour-segment, three-repeater support is a special case and will bedescribed separatelyThe ADTRAN HDSL4 system provides DS1-based services over loops designed to comply withthe guidelines given below. These guidelines apply to a single segment circuit (an HDSL4circuit with no H4Rs), to a circuit having two segments (with one H4R), or to a circuit having 3or 4 segments (with two or three H4Rs).The guidelines reflected herein are for worst-case scenarios (i.e., for loops that contain amaximum amount of disturbers, noise, etc.). Actual deployment guidelines may vary based onlocal policy. Refer to those guidelines on an as-necessary basis to ensure optimum perfor-mance.Cable Characteristics for HDSL4The loop (cable/wiring) deployment guidelines are as follows:1. All loops are nonloaded only2. Any single bridged tap is limited to 2 kft.3. Total bridged tap length is limited to 2.5 kft.4. Loop Attenuation Limits. See Table 11.Table 11. Attenuation limitsSegment Recommended MaximumUpstream Downstream1 st 30 dB 32 dB2 nd and 3 rd 28 dB 28 dB1st SegmentH4TU-C 1st H4R 3rd H4R2nd Segment 3rd SegmentH4TU-R4th Segment2nd H4R
