User manual

RS-232 interface

Flow control:

None-The communication only uses TxD and RxD signals without any hardware or software

handshaking protocol.

RTS/CTS-If the scanner wants to send the barcode data to host computer, it will issue the RTS signal

first, wait for the CTS signal from the host computer, and then perform the normal data communication.

If there is no replied CTS signal from the host computer after the timeout duration, the scanner will issue

an error indication. By setting (Host idle: Low RTS) or (Host idle: High RTS), the scanner can be set to

match the Serial Host RTS line.

XON/XOFF-An XOFF character turns the scanner transmission off until the scanner receives an XON

character.

ACK/NAK-After transmitting data, the scanner expects either an ACK (acknowledge) or NAK (not

acknowledge) response from the host. When a NAK is received, the scanner transmits the same data

again and waits for either an ACK or NAK. After three unsuccessful attempts to send data when NAKs

are received, the scanner issues an error indication and discards the data.

Inter-character delay: Refer to Inter-character delay of Keyboard wedge.

Response delay: This delay is used for serial communication of the scanner when it waits for a

handshaking acknowledgment from the host.

Operating in command mode

The scanner can operate in command mode. Commands, data and messages are sent by UART.

Commands from the Host, e.g. a PC:

1) Start Command: “0x54” (T)

Once the scanner receives 1-byte data “0x54”, it will be triggered to start barcode scanning.

2) Stop Command: “0x50” (P)

Once the scanner receives 1-byte data “0x50”, it will stop the current barcode scanning.

3) Reset Command: “0x52” (R)

Once the scanner receives 1-byte data “0x52”, it will switch off the power and then switch on the

power.

Returning message from the scanner:

1) A successful decode

Once the scanner successfully decoded a barcode, the scanner will stop scanning and returns

the barcode data to the Host.

2) Not a successful decode

Once the scanner failed to decode a barcode while receiving a Stop Command, the scanner will

stop scanning and returns a message to the Host. The message is set as “0x25, 0x25, 0x4E,

0x6F, 0x52, 0x65, 0x61, 0x64” (%%NoRead).