Python TCP Socket Programming

Question

I am having some difficulties getting my program to communicate with the two Digi modems that I have.

def sockCon ():
global HOST
global PORT
global TX
TX = "\x7E\x00\x0C\x01\x00\xA5"
BUFFER = 1024
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((HOST, PORT))
b = 1
while b == 1: 
 print ('T '+TX)
 s.send(TX.encode('latin-1')) 
 time.sleep(5)
 data = s.recv(BUFFER)
 print ('R '+decode(TX,'latin-1'), BUFFER)

Basically the problem is that when it sends it will either send completely wrong or it wont send at all and it will give me this error.

TypeError: 'str' does not support the buffer interface

Answer 1

you probably should not be doing that encode bit

TX = b"\x7E\x00\x0C\x01\x00\xA5"

should solve your problem (in python3 you need to send bytes not a string)

TX = b"\x7E\x00\x0C\x01\x00\xA5"
s.send(TX)
print( repr(s.recv(BUFFER)) )

Answer 2

If you use Python3x then string is not the same type as for Python 2.x, you must cast it to bytes (encode it).

TX = "\x7E\x00\x0C\x01\x00\xA5"
s.send(bytes(TX, 'latin-1'))

• Joran Beasley: I dont think he wants to actually encode as latin 1 ... I think he just wants to send it as bytes (although encoded might be the same) .. (yeah i just tested it encodes to exactly the same bytes with or without the latin1 bit :P)