ZKTeco FR1200 - Fingerprint and Card Verification Error

ZKTeco FR1200 Verification Error
One of our client contact us, a few days installing the device that the FR1200 from ZKTeco is no longer verifying both their Fingerprint, and Card instead giving a beeps as a feedback. We try different methods and possible problems like changing the wires, the device and even the master device and still the problem insist. So we try to look inside the device and try to look for the Communication Settings and there we find the answer.
Possible Solutions:
1st ) Check the wirings
2nd) Replace the FR1200 device
3rd) Replace the Master Device in our case its MultiBio800
4th) Configure Master Device
-Menu
-Comm
-Serial Comm
-Serial Port
Select the option "Master Unit"
If master unit is not present in the option try to update your firmware. And if still the master unit is not available then try to select any of the options and reboot the device, and if still no luck, then maybe you master device dont Support FR1200

[@noyzkieboy]

Anong type ng card gamit nyo?

[@acerot]

I only want to use FR1200 but without ZKTeco master unit. Can I get the communication protocol manual = the data FR1200 sends/receives over RS485?