Welch Allyn SCANTEAM 5770 LASER Specifications download pdf (Page 71)

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Auxiliary Port Input Communications

Protocol Selection

This selection programs the Auxiliary Port for the protocol required by the input

device to the Auxiliary Port. The protocol is a set of rules concerning the

exchange of data between serially communicating devices. The Auxiliary Port

supports Record, Burst, and ACK/NAK protocols when receiving data from an

RS-232 device.

When the Aux Port is being used as an input, data packets can be sent from the

peripheral to the Aux Port in two different forms (See "Data Character

Selection" on page 3-16).

• Record -- a single string of data that is to be sent to the host system.

• Block -- several strings of data that are to be appended together within

the base and sent to the host system as a single message.

The programmer should determine which of the four selections below best

meets the requirements of the peripheral.

• Record -- used when the transmitting peripheral is sending messages

when no confirmation of receipt is required.

• Record ACK/NAK -- same as Record, however the base responds to the

peripheral upon receipt of the message. The <ACK> (acknowledge)

character (ASCII 06 hex) is sent to the peripheral to acknowledge that a

<NAK> (non-acknowledge) character (ASCII 15 hex) is sent when the

message is not received correctly.

• Block ACK/NAK -- same as Record ACK/NAK, but the <ACK> or <NAK>

is issued upon completion of the block message.

• Burst -- used when XON/XOFF software flow control is required by the

transmitting peripheral.

*Record

Burst

Record ACK/NAK

Block ACK/NAK

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Welch Allyn SCANTEAM 5770 LASER Specifications Page 71