Hi,

I think smpplib's GSM-7 encoding is only encoding to GSM-8, but not doing the byte-packing step to convert to GSM-7.

Here's an example:

For an SMS containing "This is a test SMS from wave: é à É ô" we get this PDU in the logs: 000000550000000400000000000004b40005005741564500010032323530323132313630360000000000000100000025546869732069732061207465737420534d532066726f6d20776176653a2005207f201f206f

Taking the trailing bytes of that and converting back from hex we get:

In [5]: binascii.unhexlify("546869732069732061207465737420534d532066726f6d20776176653a2005207f201f206f")
Out[5]: b'This is a test SMS from wave: \x05 \x7f \x1f o'

Which is mostly ascii, and so can't be a 7-bit encoding. I also can't find any code in smpplib which looks like it does the byte-packing.

Maybe I'm using smpplib incorrectly?