Epson TM-T88 serial python

gistfile1.txt

# -~- coding: utf-8 -~-

## not working write

import serial
import sys
import StringIO


def fp81_write(s, payload):
    ba = bytearray()
    cks = 0
    
    ba.append('\x02')
    ba.append(b'2')
    ba.append(b'0')
    ba.append(b'E')
    
    for by in bytearray(payload, encoding='utf-8'):
        ba.append(by)
    
    for by in ba:
        if by != '\x03' and by != '\x02':
            cks = cks+by
            
    cks_digits = str(cks % 100)
    if (cks % 100) < 10:
        cks_digits = '0{0}'.format(cks)
        
    ba.append(str(cks_digits[0]))
    ba.append(str(cks_digits[1]))
    
    ba.append('\x03')
    
    print "Writing frame:"
    print ba
    
    bc = ba
    
    ba = bytearray()
    cks = 0
    
    for c in bc:
        print r"read {0}".format(c)
        
        if c == b'\x03':
            #for by in ba:
            #    print r"{0} ".format(chr(by))
                
            cks = cks - (ba[-1]) - (ba[-2]) # remove checksum from checksum

            print "Checksum: ours = {0}, printer's = {1}{2}".format(str(cks % 100), chr(ba[-2]), chr(ba[-1]))
            return ba
            
        elif c == b'\x02':
            continue
            
        else:
            ba.append(c)
            cks = cks+c
    
    print "Writing:{0}".format(ba)
    s.write(ba)
    s.flush()
    print "Written"


def fp81_read(s):
    ba = bytearray()
    cks = 0
    
    while True:
        c = s.read()
        print r"read {0}".format(c)
        
        if c == '\x03':
            #for by in ba:
            #    print r"{0} ".format(chr(by))
                
            cks = cks - (ba[-1]) - (ba[-2]) # remove checksum from checksum

            print "Checksum: ours = {0}, printer's = {1}{2}".format(str(cks % 100), chr(ba[-2]), chr(ba[-1]))
            return ba
            
        elif c == '\x02':
            continue
            
        else:
            ba.append(c)
            cks = cks+ord(c)


s = serial.Serial(port="/dev/tty.usbserial", baudrate=19200)

fp81_write(s, b'4217')
print fp81_read(s)