using zkemkeeper;
public class ZKBioLockFeature
private CZKEM machine = new CZKEM();
private int machineNumber = 1;
public bool ConnectDevice(string ip, int port)
return machine.Connect_Net(ip, port);
public void RegisterFingerprintHotKey(int userId, string name)
// Ensure user doesn't already exist
    machine.SSR_GetUserInfo(machineNumber, userId, out string tempName, out string password, out int privilege, out bool enabled);
// Register fingerprint with 3 samples
    bool success = machine.SetUserInfo(machineNumber, userId, name, "", privilege, enabled);
if (success)
// Start enrollment (finger press 3 times)
        machine.StartEnroll(machineNumber, userId, 0); // 0 = fingerprint 0 (usually left index)
        Console.WriteLine("Please press finger on sensor...");

The device firmware must handle the HOT_REGISTER state:

Many users download the wrong ZKBioLock version.

The "Register Key Hot" error often persists because Windows retains a ghost device.