PSC SP400rf manual Communications Protocol, General Features

COMMUNICATIONS PROTOCOL

The SP400RF allows configuration of several different commands that can be sent and received by the scanner, Base Station and host terminal. Programming labels to set these options and their descriptions can be found on the following pages. Configurable commands are:

ACK — Acknowledge. The host message was received and processed correctly, and no data was requested from the scanner or Base Station. (0x06)

CTS — Clear to Send. This is a command sent by an RS-232 host. When CTS is enabled, the scanner must wait for an active CTS command from the host before transmitting data. Valid only for RS-232 interfaces.

ETX — End Transmission. Label transmissions can be "framed" by optional STX (Start Transmission) and ETX characters, which are selectable by the user. (Factory default is 000—disabled.)

Item On File — The host, upon receiving a label transmission from the scanner and comparing the information with its database, found a match. (0x7E)

Item Not On File — After receiving a label transmission from the scanner, the host cannot find a match for the label in its database. (0x7F)

NAK — No Acknowledge. The host message wasn't received correctly (checksum or parity error, overrun, etc.).

STX — Start Transmission. Label transmissions can be "framed" by optional STX and ETX (End Transmission) characters, which are selectable by the user. (Factory default is 000—disabled.)

WACK — Wait for Acknowledge. This is a radio feature. When enabled, it precedes the ACK signal1.

GENERAL FEATURES

1In some systems, the ACK response is sent so quickly from the interface that it can override the WACK signal. In this case, the WACK is never perceived by the scanner.

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