atcomsystems.ca/forum Forums TDM Business Telephone Systems Comdial Telephones & Systems Comdial telephone operating voltage

Installing a feeder cable between buildings for a customer with a Comdial (?), not sure which system, digital, relatively new. Is the operating voltage for sets the same for most Comdial digital sets, if so what is it? I am adding protectors and trying to add as little headroom as possible, my options 27V or 39V. Any help, or will I need more specs on the system?? Thanks

You will be good with 39 volt protectors if it's really a Comdial system, but only for digital stations. If there are any analog stations involved, then you need to use protectors with a rating of 90+ volts to handle ringing voltage. Other brands of systems use different voltages, so you need to double check the brand, come back here and we can tell you the voltage.

Regardless of the system, please make sure to install building entrance terminals at each end that provide primary gas or solid state protector modules first. The 39 volt units should be your secondary protection, again at each end.

You need to also be concerned with the the distance of the cable for signal propagation of the data. Comdial documentation supports 1000 feet but you could go a little farther.

That 1,000 ft. limit sounds closer to a POTS phone on 24 ga cable.

Digital sets:
26 ga. - 850 ft.
24 ga. - 1416 ft.
22 ga. - 1983 ft.

POTS phones:
26 ga. - 650 ft.
24 ga. - 1133 ft.
22 ga. - 1586 ft.

Thanks for bringing my attention to my previous post. The correct distance would 1500 ft. and not 1000 ft. Also Industry standard phones can be placed at 3000 ft. This distances are for 24 gauge wire. It is possible to find different distances depending on which Comdial publication you are reading, the spec's were changed at least one time without any change to equipment. The publication I am refering to is GCA40-112