Sharp ER-A440 Service Manual page 21

2) Data transmission from satellite to the host
( 1 ) Inquines of the satellite.
( 4 ) Receives ACK.
( 5 ) Sends the text.block.
Start code
Three types of
text block formats
are available
( 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.
Dummy Terminal No.
(3bytes) (6bytes)
Text (parameter)
Text (FDS)
Text (DATA)
– 5 –
Host Satellite
ENQ
ACK
End code
NCK
ACK
EOT
( 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 NAK if any error
occurs.
( 8 ) Sends ACK.
( 10 ) Terminates the operation if EOT
is received.