Hi Karin

1.- Set ComPort.InputMode = comInputModeBinary
2.- Rest of properties according to needs
3.- For transmiting single byte
Dim buffer as Variant
buffer=ByteVar
ComPort.Output=buffer
4.- For transmiting a byte array
Dim buffer as Variant
Dim bytevar() as byte
Redim Preserve bytevar(n)=array(n) ' make a loop here
buffer=array
ComPort.Output=buffer
Also, using Input, you will get a Variant with a byte array. Check VB help.
Best regards
Daniel