User`s guide

byte (value FE hex). This low level handshaking process prevents the sender from

transmitting the rest of the sequence before the receiving device is ready.

Once the

ALERT ACK byte is received by the sender it sends the rest of the message without

any other interactions.

The length byte value describes the length of the network interface

command byte plus the length of the data field. This value will always be

at least 1. The checksum is a two’s complement of the sum of the command

byte and all of the bytes in the data field, if it exists.

If the receiver receives

a message in sequence, with a valid checksum, it responds with an ACK

(0x06). Otherwise it responds with a NACK (0x151, requesting a re-

transmission.

Sender

Link-Layer

Header

[sequence number 1

1 length 1

1 not-length 1

Receiver

1 ALERT ACK (FE)*

*Only transmitted with

ALERT/ACK link

protocol

1 checksum [

1 ACK(or NACK)

ACK: 0x06, NACK: 0x15

Figure 9.4 SLTA-10 Adapter Reliable Transport Protocol

SLTA-10 Adapter User’s Guide

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