Datalogic STAR Modem Bedienungsanleitung PDF herunterladen (Seite 52)

STARModem™

5.2.2 ACK/NACK Protocol

This parameter sets a transmission protocol which takes place between

STARModem™ (Server) and Local Host in RS232. An RF device (such as a hand-

held reader) passes its data (code read) to the modem which sends it to the Host.

The Host sends an ACK character (06 HEX) to the modem in the case of good

reception; a NACK character (15 HEX) requesting re-transmission is sent to the

modem in case of bad reception.

In the particular case where the RF device is configured for 2 way transmission and

therefore requires an answer, it is advised to set STARModem™ with the

DATA/NACK protocol. The DATA answer from the Local Host is implicitly considered

an ACK and is sent to the RF device. If instead ACK/NACK is used, the modem

generates an Empty Answer to the RF device.

CAUTION

Before selecting this parameter ensure that “ACK/NACK from

Remote Host” is disabled (see par. 5.5.5).

ACK/NACK Disabled

ACK/NACK Enabled

DATA/NACK Enabled

data

Server

data

ACK or NACK

Server

data

DATA or NACK

Serve

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Datalogic STAR Modem Bedienungsanleitung Seite 52