506t and 509u to viper 5704

509, isn't that the ultrasonic sensor? If so, they are a European idea, pain to fit we stopped using them around the early 90s when prox sensors came along.

I know the Viper 5904 install manual says "Note: Sensor ports 1 and 2 cannot support sensor 508D due to current limitations. These ports are also constant power and ground connections" I would check with the Viper 5704 install manual but I would guess it's the same.

You CAN plug them both in, just run the 508d ground to the orange GWA at H1/6.

I know this an older post but for future readers I would like to add, I have the 508d and it's set perfectly. Might as well give them a warn away as opposed to breaking the window and then getting an alert with a glass break sensor. I see no need for both either. With the 508d I get a warn away if I'm about six inches from the window and if I put my face to it the alarm will trigger.