Toshiba CTX28 manual Bptu and Rptu Cabling, Cable Length

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BPTU and RPTU Cabling

BPTU and RPTU Cabling

To meet Part 15 of FCC Rules, ISDN PRI equipment must be connected using CAT5, Shielded Twisted-Pair (STP) cabling between the CSU and the BPTU or RPTU. CAT5 STP protects against cross talk, Radio Frequency Interference (RFI), and/or Electro Magnetic Interference (EMI). STP protects ISDN signal data while being transmitted through the cable and keeps the cable itself from emitting EMI and RFI.

Important! To avoid ground loops, connect only the BPTU or RPTU end of the shielded cable to ground. The Strata CTX grounds the CAT5 cable shield between the Strata CTX and CSU at the BPTU or RPTU RJ45 jack. You do not have to connect the CSU ground drain. The CSU ground should not be connected to the cable shield.

Shield continuity must be maintained from the BPTU or RPTU to the CSU, particularly if using extension connecting cables. Keep the cable as short as possible between the CSU and the PRI Demarcation jack, because there is no shield between the CSU and the Demarcation jack.

Toshiba provides a cable kit (Part No. RPRI-CBL-KIT), that contains all that you need to connect the network ISDN jack to the network side of most CSUs and the equipment side of the CSU to the BPTU or RPTU PCB. Depending on the manufacturer, the CSU may use DB15 or modular jacks. If the CSU is equipped with the modular jacks, the DB15/modular adapters are not used. If this is the case, make sure the CSU modular jacks are not shielded jacks.

A detailed pinout diagram for the RJ45 network jack (USOC RJ48C or RJ48X) and the modular cords/adaptors are shown in Figure 7-6 on page 7-12and Figure 7-8 on page 7-13.

Cable Length

The distance between the BPTU/RPTU and CSU or the BPTU/RPTU and other Customer Premise Equipment (CPE) may vary (0~655 ft.). The BPTU or RPTU must be equalized and its impedance must match the impedance of the connecting cable.

BPTU: Set the SW settings for the proper cable length (see Table 7-3 on page 7-6and Figure 7-3 on page 7-5).

RPTU: Set the SW settings for the proper cable length (see Table 7-7 on page 7-10and Figure 7-5 on page 7-9).

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Strata CTX I&M 06/04 7-11