User's Manual

5 MODE OF OPERATION

5.1 OPERATING MODE

In order to start operating TWN4 MultiTech 3C M, it simply has to be connected directly to a host device.

5.2 POWER UP

In case of an external power supply unit is used, the following requirements must be satisfied:

• Short-circuit current < 8 A

Once TWN4 MultiTech 3C M is connected to the host, it detects the type of communications cable (e.g. USB or CAN), with which it is

connected to the host.

5.3 ENUMERATION

This is only applicable for the USB version: Once the device has been powered up, it is waiting for completion of the enumeration by

the USB host. As long as the device is not enumerated, it is entering a minimum power consumption mode, where both LEDs are

turned off.

5.4 INITIALIZATION

After powering up and enumeration (in USB mode), the device is turning on the built-in transponder reader logic. The green LED is

turned on permanently. Some RFID reader modules need some kind of initialization, which is performed in this step. After successful

initialization, the device sounds a short sequence, which consists of a lower tone followed by a higher tone.

5.5 NORMAL OPERATION

As soon as the reader module has completed the initialization, it is entering normal operation. During normal operation, the reader

module is searching for a transponder continuously.

5.6 DETECTION OF A TRANSPONDER

If a transponder is detected by the reader module, following actions are performed:

• Send the ID to the host. By default, the USB device sends by emulating keystrokes of a keyboard.

• Sound a beep.

• Turn off the green LED.

• Blink the red LED for two seconds.

• Turn on the green LED.

Within the two seconds timeout, where the red LED is blinking, the transponder, which just has been recognized will not be accepted

again. This prevents the reader module from sending identical IDs more than one time to the host.

If during the two seconds timeout of the red LED a different transponder is detected, the complete sequence restarts immediately.

5.7 SUSPEND MODE

The USB version of the reader module supports the USB suspend mode. If the USB host is signaling suspend via the USB bus, the

reader module is turning off most of its power consuming peripherals. During this operation mode, no detection of transponders is

possible and all LEDs are turned off. Once the host is resuming to normal operation mode, this is also signaled via the USB bus.

Therefore, the reader module will resume to normal operation too.