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1.1.4
Logic Level Compatibility
The following table show the compatibility of the TM8000 digital I/O used
for CCDI with common industry logic standards.
Digital Input
Compatibility and
Tolerance
Logic standard input compatibility and tolerance
Digital Input
Line
3.3V CMOS
5V TTL
RS-232
AUX_RXD
Yes
Yes
Yes
Yes
IOP_RXD
Yes
Yes
Yes
Noa
CH_RXD
MIC_RXD
PRG_RXD
Yes
Yes
Yes
Yes
a.
Level compatible but not tolerant. Inputs can be made RS-232 tolerant
by using 3.3kOhm series resistance inserted at the radio end.
Digital Output
Compatibility
Logic standard input compatibility and tolerance
Digital Output
Line
3.3V CMOS
5V CMOS
5V TTL
RS-232
AUX_TXD
Yes
No
Yes
No
IOP_TXD
Yes
Noa
Yes
No
CH_TXD
MIC_TXD
PRG_TXD
Yes
No
Yes
No
a.
1.2
5V CMOS
These outputs can be made 5V CMOS compatible using a 3.3k Ohm
pull-up resistor to 5V that is provided by the device being driven.
Before Operating
Before using CCDI, the following may be useful to check.
■
The radio must be correctly programmed for use with the CCDI
protocol. See “Radio Programming” on page 17 for configuration
information.
■
At power on, the radio will select its default channel. To change the
channel, select the channel using the normal radio interface or using the
CCDI Go_to_Channel command (see “GO_TO_CHANNEL” on
page 32).
Note that some channels are designated data channels in the Details tab
of the Channels form which means they are optimised for data.
■
The radio will power on into the mode selected in the ‘Powerup State’
field in the Data form.
■
Power, Tx and Rx LED indicators are helpful for establishing proper
operation. The radio speaker can be used to listen to data coming in.
TM8100 Computer Controlled Data Interface (CCDI) Protocol Manual
September 2003 © Tait Electronics Limited
Introduction
15