D/I Mux III User’s Manual Appendix B. –24 Volt Systems
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Appendix B. -24 VOLT SYSTEMS
The following cards are specific to a -24 Volt DC system.
Common Equipment
30118-121 T1 Interface (Requires -24 V for alarm relays)
30118-122 Enhanced T1 Interface (Requires -24 V for alarm relays)
Voice Cards
33242-124 2-Wire FXS (requires -24 Volt for Talk Battery); also requires a -24 V External
Ringing Generator. Coastcom does not include a -24 V External Ringing
Generator in its product list. Tellabs’ model 8102 has a -24/48 V option switch.
Contact Tellabs directly at (708) 969-8800.
The 2-Wire FXS (650 ohm maximum) has a limited distance range when used in -24 V systems.
Allow for one-half the cabling distance.
30058-001 C1SDCU - The C1DCU Control Unit will work in a –24 V system. However, a +24
V system will require an isolated ground. Coastcom does not provide an isolated
ground.