CDM1550 to external alarm pinout

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phillipsc84
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CDM1550 to external alarm pinout

Post by phillipsc84 »

Anyone with good knowledge of the accessory connector on the CDM1550 I need some help. I have been asked to configure the accessory pinout on three CDM1550LS radios to triger a relay when an MDC call is received. I am not to familiar with the accessory connector on this model and could use some help. All I know is that when the radio is called via MDC I need the accessory connector to supply voltage to a relay that with then trigger something else. Any thoughts? The person who requested this setup has it setup already but the one radio with the connector setup is fried and they cant read the codeplug to send me to copy.
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HumHead
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Re: CDM1550 to external alarm pinout

Post by HumHead »

The accessory connector function are defined in the Radio Configuration section of the CPS.

There are a couple of ways to do it. The first is to configure a pin for External Alarm under the Accessory Pins tab. That pin will respond to calls to the radio's MDC ID. The specifics of the External Alarm pin's behavior and function are defined under the Accessory Configuration tab in the Radio Configuration window.

Alternatively, the CDM series also has the ability to provide to auxiliary control outputs, with their own MDC ID addresses. To use these, assign an accessory connector pin to either Auxiliary Control 1 or 2, as appropriate. The MDC addresses and pin behaviors are defined under the Auxiliary Control tab in CPS.

The radio's give you a lot of flexibility. You can actually have one radio respond to three addresses (technically five, if you are counting the deactivation IDs) and provide three separately defined output functions. The CPS help file actually has a lot of good information in it.

A final note- According to Motorola, the output pins can handle up to one amp, although I try never to get even close to testing that. If you are planning to drive a relay directly off of the accessory pin, be sure to put a reverse EMF protection diode across the coil.
Amateurs train until they can do it right. Professionals train until they cannot do it wrong.
Daibach
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Re: CDM1550 to external alarm pinout

Post by Daibach »

Can the external alarm can be triggered with the Quik-Call II system using a set of tones to activate a speaker and an LED light?

Any help would be appreciated...


Thanks
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HumHead
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Re: CDM1550 to external alarm pinout

Post by HumHead »

External Alarm will work for QCII systems, as well as MDC. The Auxiliary Control outputs are MDC only.

You can use the output to drive just about anything you want, with the proper interfacing. It is just a pin that can be programmed to either go to +12V (or 13.8V, etc.) or ground when activated. Timing and reset parameters are programmable in CPS. What you do with it is up to your imagination and engineering skills.
Amateurs train until they can do it right. Professionals train until they cannot do it wrong.
phillipsc84
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Re: CDM1550 to external alarm pinout

Post by phillipsc84 »

That all sounds good. One thing I did notice in the help file for the External Alarm on Pin 4 is that it says it can only be set to "Active Low" which I am guessing is ground. Does this sound like anything anyone else has seen?
Daibach
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Re: CDM1550 to external alarm pinout

Post by Daibach »

It does point to pin 4. I get 9v from it, but when I hook up a speaker it jumps up to 13v, so I'm a little baffled as to how it activates (like a relay) with constant voltage. Time to read and learn more about CPS :lol:
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HumHead
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Re: CDM1550 to external alarm pinout

Post by HumHead »

You are probably absolutely correct about pin 4 being active low only (I'm working without CPS in front of me at the moment), which does mean that it pulls to ground when it goes active.

Connecting a speaker to pin 4 will not get you anything, except a reminder of what running DC through a speaker coil does. If memory serves, pin 4 is an open collector output, so the speaker is probably acting as a pull-up resistor, which is why you are seeing 13V with it connected.

To use the output you would connect a relay, or other interface, with one side of the coil going to a constant + voltage source, and the other side going to the accessory pin. When the output is active it pulls to ground and the relay, or other interface, is activated.

Just don't forget that reverse EMF diode if you are connecting a relay directly to the radio's pins.
Amateurs train until they can do it right. Professionals train until they cannot do it wrong.
Daibach
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Re: CDM1550 to external alarm pinout

Post by Daibach »

Ahhh sorry, didn't make that clear... I meant hook up a speaker normally (pins 1 & 16) is when the voltage went up on pin 4. Can't say I've tried hooking it up to pin 4, would make for a nice buzzzzz lol. Would I use the ground (pin 7) on the relay? I'm trying to figure out what trips the relay once the signal has been recieved.

Ty Sir'
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