I have a NEC SL1100 phone system. I am trying to use the phone to control the magnetic lock installed in the front door. I have setup the door phone, when door phone is talking to the individual phone, I would like to have the "flash" key to unlock the magnetic lock, but I have problem to get it working. Anyone can provide me information how to wire to the maglock? Thanks in advance.

Look in the Sl1100 hardware manual.

Could you give me specific instruction? I have looked into the manual for setup all other features I need, but I could not find this one. I would like to know from which port of the SL1100 to connect to the maglock. Thanks

You have to hook up the relay to trigger the mechanism. This is fairly standard stuff.

SL1100 hardware manual, in the table of contents section go to installing multi line telephone and optional terminals, here you will find installing the door unlock devices.

I did see that section 5.6 in the hardware manual, installing the door unlocking devices. I connect the pin 4-5 (relay 1) to the power supply control port "Push" and portal "GND", which should control the maglock. when I hit "flash" key on the phone, it won't unlock the maglock. I am pretty new to the system, and I might do something obviously wrong. Please kindly help to give me more detailed instruction on how to connect the wire and how to set the settings. Thanks in advance.

Did you follow all the programming in the feature and specks manual?

You have to be on a door phone call.

Yes, I have the door phone installed correctly and it is working.
From SL1100 system, RY1/2 jack, I have pin 2,7 for door 1, ping 4,5 for relay 1. The lock is connected to a power supply control, which has Push, GND, 12+, COM, NC+. Anyone can tell me how the wire from RY1/2 connected to the power control?

It should be a simple relay closure. You should be able to short the pairs and trigger the lock. If that doesn't work the relay will never work til you get that sorted out.

http://www.necsl1100distributors.com/mm5/downloads/resources/SL1100-Door-Phone-Installation.pdf

Did you test the relay with a continuity tester to see if it's shorting when you press the flash key when you are on an active door phone conversation?

The relay shorting test does not work. Do I need to do any programming? If I need, please point me to the right direction. Thanks

When I am in a door phone conversation, if press flash key, it does not short the relay. Please advise.

In the feature and specks manual you have to program the relay type, by default it is set as 0 (no relay). Once you set this you have to assign what door box will be activating it, by default it is set to 0 (not used)

This! 10-61

Thanks for the reply above. However, I still cannot make it working.
In programming section 10-61, I set relay type to "Door phone", and Destination Selection to "2" (my door phone is connected to the 2nd port)

In the RY1/2 port，I connect a multimetter to either pin 4,5 for relay 1, or pin 3,6 for relay 2 to test continuity. When I am in a door phone call, if I press "flash", it does NOT short the relay. Any idea on what else I am missing?

No idea at this point. I would call NEC at this point if they are still supporting the 1100.

If you are using the second port then 10-61 should be doorphone 2, destination 2. I'd use the third SLT port in the main KSU (DP 1) and set everything up for DP 1, destination 1. SLT ports 3/4 are used for the doorphone.