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JANUS? 2020 Hand-Held Computer (4MB) - Intermec

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NF BC Networking the Reader<br />

6<br />

PC Standard Protocol PC Standard handles data transfer on a character-bycharacter<br />

basis or by either filling a receive buffer or transmitting a buffer of<br />

data. This protocol is designed to be compatible with the standard PC BIOS<br />

functions. The one exception is that the PC Standard protocol can buffer data<br />

that is received to avoid losing characters if a program has not checked for data<br />

recently.<br />

Point-to-Point Protocol Point-to-Point is an unsolicited protocol in which the<br />

reader transmits data whenever it has something to transmit. The data is<br />

followed by a CR LF as the EOM characters. The reader is always in a receiving<br />

state and does not wait for select commands. This protocol does not perform<br />

any error checking or acknowledgment handshaking.<br />

Point-to-Point protocol is typically used to connect the reader to a CRT<br />

terminal or host computer. Since Point-to-Point is an unsolicited protocol, you<br />

can initiate the transmit command from the reader or the host.<br />

Polling Mode D Protocol Polling Mode D requires the host computer to ask the<br />

reader for data it might have (polling) and to request to send data to the reader<br />

(selecting). PC-IRL uses this protocol.<br />

RF Protocol RF Protocol is used in radio frequency (RF) networks only. For<br />

details, see your <strong>JANUS</strong> RF documentation.<br />

User-Defined Protocol User-Defined is a powerful protocol because you can<br />

configure the protocol to your own requirements. For example, you can<br />

configure User-Defined to act like a Point-to-Point protocol, except that it<br />

requires an LRC and an acknowledgment from the receiver. You can also<br />

define the communications characters such as SOM, POL, or SEL, or disable<br />

these characters by setting them to null.<br />

You can also use User-Defined protocol to define User-Defined Multi-Drop<br />

protocol. In User-Defined Multi-Drop, you must set the POL and SEL protocol<br />

characters in a predetermined combination. For help, see “POL and SEL<br />

Combinations for Multi-Drop Protocol” in Appendix C.<br />

6-11

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