ER-A490 (serv.man4). ERA490 Option Service Manual - Sharp ECR Service Manual (repair manual). Page 7

ACK

EOT

( 1 )  Inquines of the satellite.

( 4 )  Receives ACK.

( 5 )  Sends the text.block.

( 7 )  Resends the text block if NAK is received.
        Resends the text block up to two times.
        Sends EOT and terminates the operation
        with error if NAK is still received after the
        second resending of text block.

( 9 )  Sends the next text if ACK is received and
        sends EOT and terminates the operation if
        data transfer is finaiized.

( 2 )  Receives ENQ.
        Check the terminal No.
        to see if it is its own.

( 3 )  Sends ACK.

( 6 )  Receives text.
        Checks the check sum,text
        data,etc. And goes to (8)
        if there is no error in them.

( 8 )  Sends ACK.

( 10 )  Terminates the operation if EOT
          is received.

ENQ

Host

Satellite

Dummy
(3bytes)

Terminal No.
(6bytes)

Start code

Text (parameter)

End code

Text (FDS)

Text (DATA)

Three types of
text block formats
are available

NCK

ACK

( 8 )'  Sends NAK if any error
         occurs.

1 – 6