Sharp ER-A57R1 Service Manual page 27

2. Connection between the terminal and
MODEM
SD : TRANSMITTED DATA
RD : RECEIVED DATA
DTR : DATA TERMINAL READY
DSR : DATA SET READY
( 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.
RTS : REQUEST TO SEND
DCD: DATA CARRIER DETECTOR
CTS : CLEAR TO SEND
CI : CALLING INDICATOR
FG : FRAME GROUND
Dummy Terminal No.
(3bytes) (6bytes)
Text (parameter)
Text (FDS)
Text (DATA)
2 ™ 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.