Encoded Data Packet Format
Transmission format is 1kbps differential Manchester encoding when using 3.58MHz resonator.
Oscillator frequency can decreased to suit narrow band RF module data rate requirements. CTR124H
IC running at 20MHz can be used with wideband radio modules for fast data transmission.
0
0
0
1
0
1
0
1ms
1
500µs
1
Figure 4: 1kbps differential Manchester coding of ‘1’ and ‘0’
Control124 transmits a 6-byte burst, with 8 bits of preamble and 4 bits postamble. When firing up the
transmitter from cold Control124 puts in an extra 55ms especially for Narrow Band FM transmitter
and receiver requiring longer power-up to stable data time.
Figure 5: Push button transmission with 55ms power-up preamble
The large amount of sync code, address and checksum reduce the likelihood of false calling on noise to
an insignificant degree, while the breaking up of the data sequences with bit7 zeros is to reduce the
likelihood of the decoder mistaking particular sequences in the data for sync codes.
Radiometrix Ltd
Control124
page 4
RADIOMETRIX [ RADIOMETRIX LTD ]
