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CCDI
TM8100/TM8200 Computer-Controlled Data Interface (CCDI) Protocol Manual
© Tait Electronics Limited
April 2007
time could cause the buffer to overflow and for data to be
lost.
CTS
The CTS line is deactivated when there is less than 35 bytes of empty space
in the buffer.
The CTS line is activated when the CTS line had previously been
deactivated and there is now less than 10 bytes of data in the buffer.
1.7
CCDI Transparent Mode
In Transparent mode, the radio acts as a modem, automatically transmitting
in FFSK or THSD format the serial data received from the PC. In this mode,
the baud rate between the PC (DTE) and the radio (DCE) can be set to
either 1200, 2400, 4800, 9600, 14400, 19200, 28800 or 115200 (TM8200
only) baud using the programming application. The over-air data rate is
1200 or 2400 bps for FFSK data, 12 kbit/s for Tait High Speed Data
(THSD) narrow band and 19200 bit/s for THSD wide band. The serial data
input buffer is 512 bytes for the TM8100 and 600 bytes for the TM8200, to
adequately cope with the data flow.
Communication in Transparent mode is free-format, with the protocol
determined entirely by the PC and the modem. It is transparent to the
CCDI, allowing the PC to send and receive data without passing through
the CCDI. CTCSS and DCS subaudible signalling is available in FFSK
Transparent mode only.
1.7.1
Entering Transparent Mode
Transparent mode can be set as the default mode at power on by selecting
FFSK or THSD Transparent Mode in the ‘Powerup State’ field in the
programming application. Refer to
You can change to Transparent mode while operating in Command mode
by sending a TRANSPARENT command to the radio or using a
programmable I/O line programmed for THSD. Example: t01zB1 sends a
TRANSPARENT command, requesting that the radio be put into
Transparent mode. The escape character specified here is “z” (ASCII code
= $7A). Once acknowledged, any further data is linked directly to the radio
in Transparent mode.
If the radio default is set to Transparent mode at power on, the default escape
character is “+”.
