Programming instructions

Intermec Fingerprint 6.13 – Programmer's Guide

7. INPUT TO FINGERPRINT, cont'd.

9. RS 422/485

Communication, cont'd.

RS 485

RS 485 is only available on the optional RS 422/485 interface board

(communication port "uart2:"). It is a 2-line screen cable point-to-

point or multidrop loop connection, where the two lines switch

between transmitting and receiving data according to instructions

from the software. By default, the port is set to receive data. Before

transmission of data, the port is switched to transmit. After the last

character has been transmitted, the port is switched back to receive.

• Point-to-Point

For a point-to-point RS 485 communication between a host

computer and a printer, or between two printers, no special

protocol is required. No handshake can be used, but communication

control must be taken care of by the application software.

Set the printer's flowcontrol setup parameters as follows:

RTS/CTS: Always Disable

ENQ/ACK: Always Disable

XON/XOFF, Data from host:Always Disable

XON/XOFF, Data to host: Always Disable

Prot. addr: Disable

Either the standard IN/OUT channel should be set to 2, or the

device "rs485:" should be OPENed for INPUT, e.g.:

OPEN "rs485:" for INPUT AS #1

• Multidrop Loop

This type of communication is intended for sending packets of

data from a master unit (usually some kind of computer) to any

of a number of connected printers ("slaves"), according to a

destination address included in message. The addresses of the

printers are specified by straps on their RS 422/485 interface

boards.

Transmissions should consist of packets of data with a maximum

size of 255 bytes. Longer records must be divided into two packets

or more.

When a printer is set up for “Prot addr. enable”, it will

automatically use a special protocol described later in this chapter,

but a connected host computer must be provided with some

application software that composes its transmissions accordingly.

No handshake can be used, but communication control must be

taken care of by the application software.

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Verbosity

Also see:

• Chapter 7.7