These devices connect to a phone system KSU. They add voice-mail support and storage to the telephone system.

This controller lets you control up to 10 modules from any touch-tone phone in the world! Ideal for cooling down or heating up ski houses or summer homes. Can also flash lights when the phone rings; ideal for the hearing impaired. Note: Does not work well on the same line with an answering machine or modem that is setto answer the phone.