I have a GC Simon wireless alarm system (model: 60-911-010-4-IE) and one of my door sensors has developed a problem and needs to be replaced. However I am having great difficulty in sourcing a suitable replacement. I did by a recommended replacement from the USA but this did not work. I think because the system I have is 433Mhz and the new sensor was 319Mhz. Can you recommend a replacement sensor and where I may purchase same.
Thanks in advance and regards