36
CCDI
TM8100/TM8200 Computer-Controlled Data Interface (CCDI) Protocol Manual
© Tait Electronics Limited
April 2007
■
[MESSAGE] is optional. The field is limited to 32 hex characters in
standard ASCII range 20h to 2Fh. Characters between 00 and FFh can
be sent but characters above 7Fh can not be displayed.
Examples
s0A051234567813
transmits data identity “12345678” with 100ms
lead-in delay through current channel.
s0CFF12345678Hi39
transmits data identity “12345678” and SDM
data “Hi” with 5.1s lead-in delay through current channel.
1.9.8
TDMA
The TDMA commands consist of three sub-functions for opening a TDMA
channel, sending TDMA data, and closing a TDMA channel.
Opening a TDMA
Channel
Before sending or receiving TDMA data, a TDMA channel must be opened
using the OPEN_TDMA_CHANNEL command.
The OPEN_TDMA_CHANNEL command instructs the RU to prepare
TDMA services on a specified TDMA channel (conventional mode) and to
configure the modulation scheme and packet size according to the settings
in the database.
Note
A TDMA channel is different to a “normal” channel with the
same channel number.
Sending TDMA Data
Sending TDMA data requires a second TDMA command,
QUEUE_TDMA_DATA_FOR_SENDING. This command requests the
RU to queue data in a dedicated TDMA data buffer for transmission.
The QUEUE_TDMA_DATA_FOR_SENDING command passes a
maximum of 128 data bytes to the TDMA module. However, the data size
actually used for over-the-air transmission is a programmable parameter for
each channel. The TDMA transmission module will ignore any data
exceeding the programmed packet size of the current channel.
Should the data size in the CCDI command exceed 128 bytes, then an error
message (Command not accepted error) will be returned.
If the specified channel is not programmed for TDMA data transfer, or if the
specified channel had not been opened for TDMA using the
OPEN_TDMA_CHANNEL command, then CCDI will return a TDMA
status message indicating the failure of the command execution.
A second QUEUE_TDMA_DATA_FOR_SENDING command can only
be accepted after the progress message “TDMA DATA QUEUED FOR
