highbyte = 0x02;
Serial.write(highbyte);
for(inoffs = 0; inoffs < PKT_LEN; inoffs++) {
    intmpbyte = inpacket[inoffs];
    highbyte = ((intmpbyte >> 4) & 0x0f) + 65;
    lowbyte = (intmpbyte & 0x0f) + 65;
    Serial.write(highbyte);
    Serial.write(lowbyte);
}
highbyte = 0x03;
Serial.write(highbyte);