horn honk on alarm without honk output?

I have often wondered if it is possible to make the horn honk only when the full alarm is triggered? Connecting a simple relay to the positive siren wire to activate the horn would lead to the horn being activated with the arm/disarm/warn away chirps, and to constantly sound rather than honk. Thanks in advance

Yes, there is a light flash output. Having thought about that, I assume this approach would involve the use of three SPDT relays? Relay 1: switched on by the siren to give up 12v to relay 3 Relay 2: convert parking light positive output to earth output Relay 3: switch with output from relay 2, to send +12v to horn (with horn end connected to both normally open and normally closed) I guess I'm a little bit of a noobie at these things, so perhaps there's a more elegant/simple way to get it done? :)

I was thinking about using two relays.  One triggered via siren.  The other triggered via Light output.  Supply 30 of the siren relay with whatever your horn needs.  87 of the siren relay to 30 of the light relay.  87 of the light relay to your horn.

What we do at our shop is use an EZ horn in which you can get at switch-smart.com It has a constant input from the siren and will output a "honk" pulse negative or positive.

Take your light output, if pos. connect a lead to this, after the join, insert a1N54xx diode with the bar pointing away from the alarm, take wire to relay 86, ground 85, 12v+ fused 10amps to 87 and 30 to horn. If OEM horn, check to see if neg or pos fired, ie it either sits on pos and is fired  by switching to ground or vice versa. If the first, feed ground to 87, if the second, leave as in above.

why don't you guys use marksman this alarms are good and they  have all this features built in you can program the the oem horn anyway you like ,honk with lock unlock or only when it goes off 

you can program most dei alarms to pulse the siren output rather than constant AND program chirps off.MECP Master Certified Technician

ASE A6 Certified Technician