PL cable considerations
The Clear-Com intercom line is intended to run on one shielded cable pair per intercom channel. One conductor carries audio, and the other
conductor carries the DC power for Remote Stations. The shield serves as the ground return for the audio and power conductors. When choosing interconnect cable, keep the following considerations in mind:
Keep cable runs under 500 feet (150m). The DC resistance of the ground or common conductor affects crosstalk. For permanent installation runs longer than 500 feet (150m), do not use wire smaller than 20 gauge. The capacitance of the interconnect cable affects system frequency response and sidetone stability. Total capacitance should not be greater than 0.25 uF.
Ground Isolation: The Pin 1 ground connection of each XLR connector must be isolated from the chassis. Pin 1 should not be connected to the shell of the XLR connector.
Multi-pair Cable: Individually shielded multi-pair cable is acceptable for use in multi-channel systems. For crosstalk considerations the shields must be tied together on both ends of the cable to produce the lowest possible DC resistance path for the ground return.
Portable Installation Cable: Practical cable for portable system interconnections is flexible, two-conductor, shielded microphone cable. We suggest using BELDEN #8413 (24 Gauge). For runs longer than 500 feet (150m) use a 20 gauge cable or larger (BELDEN #8412).
Permanent Installation Cable: Vinyl-jacketed shielded pair is the cable of choice for permanent installations. Placing the cable in conduit is recommended but not necessary.
Suggested Cable Types: The following chart lists the specifications of various BELDEN cables: