I recently brought a RFID reader from AliExpress (I will put link below) which reads both my NExT implant (13.56 side) and my XM1 without any problem. I have this connected to a controller also from eBay (link below). The controller has NC and NO outputs, both passive (so just connecting a circuit) and live (12volt), and can be set for a toggle or for a pulse output (with changeable time).
The controller will also work with a LF reader, but only with EM card not HID (at least I couldn’t get it to work with my HID).
I have this working as my garage door opener and have no problems with range (about 1-cm for both chips). The reader is powered by a consistent12 volt DC current, which I reckon effects reading range.
As such, if you get something like the above, you should be able to use your exisitng xEM if it is emulating an EM card and not HID or use either side of the NExT.
I have no ties to either of these suppliers, other than the fact I purchased from them both and was happy with what was supplied. I have spent the last few weeks making tonnes of orders for RFID readers to try and find some that actually work with my NExT and XM1 without any issues.
reader: (you need to select whether you want LF or HF whe checking out): Waterproof 125KHz 13.56Mhz Compatible Proximity RFID Card Reader Wiegand 26 Reader Door Access Control System Kit|Control Card Readers| - AliExpress
controllor: Door Access Control System Switch Power Supply DC 12V Access Control Machine | eBay
I hope this helps you.
TS