I have a CR1000 datalogger and im comunicating over RS232 with a modem (iridium rockblock plus). To send messages in a binary form after the data bytes, 2 bytes of checksum has to be added to the packets.
Many times the checksum and within the binary data bytes will contain 0s (or null characters).
I cant find a way to transmit those bytes. Since the checksum cannot be altered the trick of converting 0s into other value wont work.
Also tried to send separated Long variables and &H00000000. In other forum someone said that if transmited alone 4 bytes Longs will be transmited as binary not beeing converted to string by the logger but it wont work, for example a Long variable setted as 1 will be transmitted as 1 byte =1 (instead of 4 bytes [0 0 0 1]).
So ¿Is there any way to send a byte 0 to the serial port?