Garbled output on Telnet Client about pywinpty HOT 10 OPEN

import logging
logging.basicConfig(level=logging.DEBUG)
from winpty import PtyProcess as PtyProcessUnicode, Backend
import time
import codecs
import socketserver

pty = None

OUTPUT_CACHE = b''

class ptyTCPHandler(socketserver.BaseRequestHandler):
    """
    The request handler class for our server.

    It is instantiated once per connection to the server, and must
    override the handle() method to implement communication to the
    client.
    """

    def setup(self):
        super().setup()
        # Add to client list
        print(f"Adding {self.client_address} to client list")
        clients.append(self)
        return(0)

    def handle(self):
        global OUTPUT_CACHE
        # self.request is the TCP socket connected to the client
        # self.request.sendall("Hello there!!".encode())
        self.request.sendall(OUTPUT_CACHE)
        while True:
            self.data = self.request.recv(1024)
            logging.info(f"TCP handler recvd: {self.data}")
            pty.write(self.data.decode())

            try:
                ch = pty.read(65536)

                OUTPUT_CACHE += ch.encode()
                for client in clients:
                    print(f"Writing {ch.encode()} to {client.client_address}")
                    client.request.sendall(ch.encode())
            except Exception as e:
                print(f"#### EXCEPTION: ptyTCPHandler: {e}")
                break
    def finish(self):
        print(f"Removing {self.client_address} from client list..")
        clients.remove(self)



if __name__ == "__main__":

    subproc_name = "cmd.exe"
    # subproc = "python.exe"

    pty = PtyProcessUnicode.spawn(subproc_name, backend=Backend.WinPTY)
    # pty = PtyProcessUnicode.spawn(subproc_name, backend=Backend.ConPTY)

    pty.decoder = codecs.getincrementaldecoder('utf-8')(errors='replace')
    pty.name = subproc_name
    print(f"pty size: (rows, columns): {pty.getwinsize()}")

    # Get first few lines from process startup
    time.sleep(0.5)
    OUTPUT_CACHE += pty.read(65536).encode()

    # Start socket server

    HOST, PORT = "localhost", 11000

    # Create the server, binding to localhost on port 9999
    with socketserver.TCPServer((HOST, PORT), ptyTCPHandler) as server:
        # Activate the server; this will keep running until you
        # interrupt the program with Ctrl-C
        print(f"TCP Server running on {HOST}:{PORT}")
        server.serve_forever()

exit(0)

0;C:\Windows\System32\cmd.exeMicrosoft Windows [Version 10.0.18363.1556][9C
(c) 2019 Microsoft Corporation. All rights reserved.
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D:\sandbox\epics\pyProcServ\area_51>[16C 

D:\sandbox\epics\pyProcServ\area_51>ddirir                                                                                                                       
Volume in drive D is DATA[35C                                                   
Volume Serial Number is DCBD-282A[27C                                          
[61C                                                                             
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[61C                                                                            
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2021-12-09  10:24 PM                18 dir.bat[15C                              
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2022-08-10  05:12 PM             4,538 winpsuedoterm.py[25C                     
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0;C:\Windows\System32\cmd.exe                                                                                
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