PHOTOELECTRIC BEAMS (or BEAM DETECTORS): This is an INPUT DEVICE that comprises an emitter and a receiver both of which must be in sight of one another. In security type applications, the detector uses a narrow focused beam of infrared light that when broken will result in a fault or alarm. BEAM FIRE DETECTORS operate on a similar principal. The sensor is designed to respond to specific inputs that allow it to discern the difference between SMOKE and HEAT within the protected environment. A complete or partial blockage of the beam in this type of application will result in a TROUBLE condition however, not an alarm.
PMA: Short for PERIODIC MAINTENANCE AGREEMENT. This is a contract between the building owner (or property manager) and (normally) a fire equipment service company to perform semi-annual and annual testing and maintenance of the life safety equipment on a site.
POTS: Short for PLAIN OLD TELEPHONE SERVICE. In British Columbia this is provided by primarily by TELUS. It's essentially the service that's been a staple throughout North America for the last ninety-plus years. Services are routed to the building through overhead lines (or underground) to a central location where it's distributed to the various telephone devices. These days a lot of the old "copper" wires have been replaced with much more efficient fibre-optic cable. This allows for faster transmission and much more data "throughput".