The Ademco SA5140-1 is a wiring harness kit designed to connect two alarm control panel backup batteries in parallel so that your alarm system will work for longer if and when you lose power to the system.
Wired alarm systems, like Honeywell's VISTA control panels, get power from an AC transformer that plugs into a standard wall outlet. The AC transformer (1361 or 1321 are popular transformers used with VISTA panels) plugged into the wall outlet steps down the high voltage power from the wall outlet and transforms it to low voltage 16.5 VAC output which powers the alarm control panel. Internally, the alarm panel then acts as a power supply itself to provide power to keypads, alarm receivers, alarm communicators, 4-wire alarm sensors, etc. Any professional alarm system will also have leads for a battery charging circuit so that you can hook up a backup battery so that your system will continue to work during a power outage (or if someone cuts the wire to your AC transformer).
We offer the Ultratech 1240 (4Ah) and the 1270 (7Ah) backup batteries but there are numerous types of similar sealed-lead acid batteries that you can use to provide backup power to your alarm system. Depending on how much power you are drawing from your panel's auxiliary power (for the keypads, receivers, communicators, sensors, etc) and the size of your battery, you can determine how long your system should stay operational during a loss of AC power. The higher the amperage hours (Ah), the longer the backup run-time.
If you are not happy with the amount of time your alarm system is staying powered on when switched over to backup battery power, you can use the SA5140-1 to wire up two separate backup batteries, in parallel so that it doubled the amperage hours and provides longer run-time during a power outage. Your alarm system's installation guide should have information about how long your panel will stay on during a loss of AC power. With a Honeywell VISTA-20P alarm system, a 4Ah battery will keep the panel running for 24 hours if you are drawing only 45mA from the panel's auxiliary power output. Both the Ultratech 1240 (4Ah) and the 1270 (7Ah) will fit side by side in the bottom of the metal alarm cabinet. However, the 1270s will be very tight so if you have other things on the bottom shelf of your alarm control panel, you probably won't be able to fit two 1270 batteries.