Scantronic Homelink 55 - Rf Expander Issue

Hi,

I'm hoping for a bit of advice if possible, i am installing a scantronic homelink 55 system in my friends house and i have set up the panel with the wired zones and got the keypad and bell working fine but i tried to install the rf expander and it was having none of it.

It says you can wire it in a star method so i have one cable coming from the bus connections to the keypad and another separate cable going to the rf expander (8 zone) but when i connect the data cable with the sysem powered off as it states and then turn it back on instead of 2 clean beeps its making a weird noise as if its getting interference and the screen is flashing 88 and making a noise every 3 seconds as if its responding to the data pulses but its not letting me do anything.

i was hoping if someone could clear this issue up for me as i have installed a few of these systems before and never come across this issue.

Thanks for any help in advance

James