Help finding Crosspoint Switch?

[Acetronics2]

Hi,Muddy

Was a good idea to ask you for the context ...

What about a CD 4052 "Dual 4 Channel Multiplexer" ??? One half for the rows and one half for the lines ...

just need 5 lines ( 4 + enable both ...) from the driving PIC ...

Alain

[keithdoxey]

What about a CD 4052 "Dual 4 Channel Multiplexer" ??? One half for the rows and one half for the lines ...

just need 5 lines ( 4 + enable both ...) from the driving PIC ...

Alain

I would have suggested that but 4052 is intended for Stereo switching so both sides share a common address

( I am using the 4052 to give me 4 serial ports on a 18F452 )

Forgot about "Enable" on my solution but as only 3 out of 4 combinations would be used on the "column" select then the 4th option would give an open circuit so all done with 4 lines

[Acetronics2]

AAAAAAArggggghhh, damned !

you're right Keith !!! that needs two CMOS packages ... at least one 4052 and one 4053 or a pair of 4052 ... but can deal with 2 arrays !!! or, of course 2 x 4051 !!!

Alain

[BobK]

Hi Muddy,

Being an alarm installer by trade I tried doing this to a Napco MA3000 panel several years ago. After a couple of hours of trying different things including the 4066's on the keypad lines, I asked the guy I was doing this for for the version of software the panel was operating on. The latest version had a feature that allowed a zone input to be programmed to act as a keyswitch to arm and disarm the panel. It worked out great for the project. A wine cellar in a church basement where sometimes the people would forget to re-arm the system. My add-on watched for the door to close. If the system wasn't armed and the door was open, the add-on would sit and wait for the door to close. If the door was closed and they didn't turn the system on within 1 minute my add-on would re-arm the system.

I always look for ways to connect to a system that won't violate the U.L. Listing on the panel. Making something that would enter a code where you have modified the device could end up costing you should anything ever happen that could prevent the system from detecting whatever it is suppose to detect. Most systems today have wireless keyfobs. Perhaps you to tie into the contacts on the wireless key and use that to trigger the system. There are only a couple of systems that have a U.L. Listing on their wireless devices.

BobK

[muddy0409]

Yeah, we thought of the zone = keyswitch thing, but one of his many wants is for the panel to still be able to identify and report users/keyholders or whatever you call them over there.
So really the only way is to still operate the system via the keypad, albeit, by cheating!
He is aware of the possible legal ramifications of this, but is willing to accept the risk.
Anyway, that's HIS problem.
I'm just designing the thing, not doing any alterations to the panels or keypads.


Did the PCB last night/this morning (Yaaawwwnnn) using 4066's and was not as difficult as I thought it was gunna be. Got enough drive lines (10) from an 18 pin PIC, just gotta work out the mapping and plenty left over for the serial in from the prox reader (1). Did have to go double sided though, so these will have to be made commercially rather than "home brew".
BTW, the system is a CADDX CONTROLS NX unit so if you do happen to have any info on the data that goes between the panel and keypad, it would be appreciated.
The data stream uses only one line for both send and receive so it is easy to read it, but working out what means what is a bit beyond this little black duck. And besides, I ain't gettin' paid enuff.
The local distributors always say they can't supply anything along the lines on information, so..........................