TM8100/TM8200 Computer-Controlled Data Interface (CCDI) Protocol Manual
CCDI
17
© Tait Electronics Limited
April 2007
1.7.2
Exiting Transparent Mode
To change to Command mode while operating in Transparent mode, you
can:
■
send the escape sequence consisting of a 2 second idle time, followed by
three escape characters (sent within 2 seconds), followed by a further 2
second idle time.
Example: If the escape character is “+” (default), send
[2 second idle] +++ [2 second idle].
■
exit via the I/O line programmed for THSD, if Transparent Mode was
entered using this line.
1.7.3
Transparent Mode Format
Transparent Mode
Packetisation
Transparent mode data is packetised into data blocks before it is sent over-
air. The start and stop bits are removed and a header is sent at the start of
each data block.
FFSK Transmission
Format
The Transparent Mode transmission format is as follows:
Singe Data Block:
Multiple Data Blocks:
Lead-In
Delay
Lead-Out
Delay
time...
data block 1
data block n
over-air
PC
data
RS232
data
RS232
PC
air-interface data out
serial data out
air-interface data in
serial data in
processing...
radio
Flow
Control
Flow
Control
no Flow Control
air-interface data out
serial data out
air-interface data in
serial data in
processing...
radio
Lead-In
Delay
preamble
2 bytes
sync
2 bytes
size
2 bytes
FFSK data block
max 46 bytes
CRC
2 bytes
Lead-Out
Delay
HEADER
Lead-In
Delay
HEADER
6 bytes
FFSK data block . . . .
max 46 bytes
CRC
2 bytes
HEADER
6 bytes
FFSK data block
max 46 bytes
CRC
2 bytes
Lead-Out
Delay