Operating instructions

1892 1344 - SX450G Transceiver Operator Guide v1.7 / Nov 2007 11
Serial Channel Selection
v PL1 pin 6 must be logic low (<0.8V) to specify serial channel selection. This
is automatically the case when connected to an idle RS232 data output.
v Channels 0 - 255 are available in this mode
The channel can be changed by sending a serial channel number as a single RS232 byte
on PL1 pin 6. The SXn50.exe software has the ability to do this, or you can use your own
equipment.
A simple adaptor such as the one in Figure 6 can be used to connect a PC to the unit.
(The programming adaptor of Figure 10, which can be purchased from Wood & Douglas,
product code 01106 1503 A, is also suitable.)
If you use a computer which does not have an RS232 serial port, then a USB-to-serial
adaptor is also needed, described in Appendix 2 on page 27.
The SX450G also requires a power supply capable of sourcing approximately 60mA.
Figure 6 - Serial channel change adaptor
The protocol is:
9600 baud, RS232 levels, 1 start bit - 8 bit data - no parity - 1 stop bit
Single-byte, channel number in binary, LSB first (decimal 0 to 255)
Idle state for at least 40ms before and after byte.
As soon as the message is recognised as a valid RS232 byte, the channel is changed.
No confirmation is required.