cat_freq.py

#!/usr/bin/python

""" A simple program to read the frequency from my FT-847 using CAT
through the serial port on the radio and a USB <=> Serial adapter
on my iMac
"""

import serial, time
result = 0
EOM = "\xfd"

freq = serial.Serial("/dev/cu.usbserial-A900aaUV" , 9600 , timeout = 1) #Assign the USB<>Serial port to "freq"
freq.open() # Opens the port for communications
freq.write(chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00)) # Open CAT connection
freq.write(chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00)+chr(0x03)) # What's the VFO freq?

cat_recev = []
byte = ""
while byte != EOM:
    byte = freq.read()
    if byte == "": break
    else:
        cat_recev.append("%02x" % ord(byte)) # Converts the Hex result into a numbers then puts it into a list

freq.write(chr(0x00)+chr(0x00)+chr(0x00)+chr(0x00)+chr(0x80)) # Close the CAT connection
freq.close() # Close the USB<>Serial port

temp_freq = "".join(cat_recev) # Takes the list and converts to a string
temp_freq = temp_freq[0:3] + "." + temp_freq[3:6] + "." + temp_freq[6:8] # Formats the output of the frequency
freq_out = temp_freq.lstrip("0") # Strips out leading 0's from display if below 100 MHz

# Takes the last numbers from the string and assigns it to the correct VFO mode
if cat_recev[-1] == "00": vfo_mode = "LSB"
elif cat_recev[-1] == "01": vfo_mode = "USB"
elif cat_recev[-1] == "02": vfo_mode = "CW"
elif cat_recev[-1] == "03": vfo_mode = "LSB CW"
elif cat_recev[-1] == "04": vfo_mode = "AM"
else: vfo_mode = "FM"

print "\nThe current frequency is: " + freq_out, "MHz", vfo_mode + "\n" # The end result