With so many manufactures on the market when it comes to Electronic Keypads its a real struggle to consider the right choice for the right application.
To help you a little in your thought processes here are a few options to consider and what I think are good little key pads with their pros and cons
Some general things you need to consider however, would be the power supply, most are 12 Volt DC, however, some are 12 Volt AC as well, also 24 Volt AC/DC versions are available. Most Access Control Systems run on 12 Volt DC.
Some systems are inter-faced with door entry systems, in which case do not be surprised that the keypad is fed via 12 Volts AC They use AC a lot in intercom systems to act as a carrier voltage for the intercom.
24Volt DC is another common voltage and you will normally find these systems when inter-faced with Fire alarm systems. Fire Alarms normally run on 24 Volt DC.
Then, you need to consider the switching options, Some keypads use transistors to switch voltages then some use relays. My personal choice would be to have a relay version. The transistor type versions give you a positive voltage output, Like the Paxton K series keypads. The relay versions dont have any output but with the relays being voltage free does allow you to switch whatever you want. Transistor switching can also be limited to one amp, whilst relay version may be able to switch up to five amps. On the relay version you most probably would have the terminals marked NO C NC these mean Normally Open, Common and Normally Closed.
You need to put your feed voltage to the C Terminal, then depending on the output you need, for example, if your feeding a magnet your switch wire would connect to the NC terminal. If you are feeding a fail secure strike release then the opposite would be considered, NO.
Not that you cant do this with a transistor keypad as well, as most will allow you to change the output to do this.
If you have mixed voltage systems, for example you need to switch 24 Volt DC and your keypad is fed from a 12 volt source then the relay version wins hands down every time.
Where is the keypad going to be fitted is very important, most reputable key pad manufacturers state their IP rating for their keypads, but we always recommend to fit where best to give the keypad a little shelter if possible from the elements. One of my preferred keypads for all weather applications would be the Alpro Keypad, OK, not the cheapest on the block, but I have fitted these myself, in a local ferry terminal where the fresh sea air is not the kindest at times and they have stood up to a hammering very well.
Paxtons standard K series keypads have backlit LED and well as ACT keypads, great for night time use when there is no light, put also be careful that they dont draw attention to themselves.
When your fitting Magnets or electronic locks there may be a need to have a push to release button on the safe side of the door. when a magnet is fitted to a door, or an electric lock, pressing a push to release button may only disconnect the power supply for the period of pressing the button, this is normally very fussy as you need to be opening the door at the same time as pressing the button, otherwise as you release the switch the door will re-lock. most good quality key-pads have a facility to accept a push to release button. The keypad can then make active a timer circuit, say for 3 or 5 secs delay, now you can press the button and release, then use the same hand to open the door, as now the door will stay un-locked for the period of the delay.
In my view consider these keypads as some good pieces of kit.
I very much hope that you have found this mini blog helpful, should you need more info, however, we are only a phone or email call away.
Head of the tech department
TRUST Security - Trust LocksOnline