ARPANET计算机使用的是一种叫做NCP的协议进行通信。NCP（Network Control Program）是早期互联网的基本协议，相当于现在TCP/IP协议的前身。以下是使用Python模拟ARPANET通信的示例代码：

import socket

local_host = '127.0.0.1'
local_port = 8000

remote_host = '127.0.0.2'
remote_port = 8000

# 创建本地socket并绑定端口
local_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
local_socket.bind((local_host, local_port))
local_socket.listen(1)
print(f'Local socket listening on {local_host}:{local_port}...')

# 创建远程socket并连接
remote_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
remote_socket.connect((remote_host, remote_port))
print(f'Remote socket connected to {remote_host}:{remote_port}...')

# 监听本地socket并发送数据
connection, address = local_socket.accept()
print(f'Connection established from {address[0]}:{address[1]}...')
while True:
    data = connection.recv(1024)
    if not data:
        break
    remote_socket.sendall(data)

# 关闭socket
print('Closing sockets...')
remote_socket.close()
local_socket.close()

注意：以上代码仅为示例，实际的ARPANET通信过程复杂且历史悠久，很难用简单的代码模拟。