DOSBox v0.72 - Serial Multiplayer feature

DOSBox can emulate a serial nullmodem cable over network and internet.
It can be configured through the [serialports] section in the DOSBox
configuration file.
To create a nullmodem connection, one side needs to act as the server and
one as the client.
The server needs to be set up in the DOSBox configuration file like this:
serial1=nullmodem
The client:
serial1=nullmodem server:
Now start your game and choose nullmodem / serial cable / already connected
as multiplayer method on COM1. Set the same baudrate on both computers.
Furthermore, additional parameters can be specified to control the behavior
of the nullmodem connection. These are all parameters:
* port: - TCP port number. Default: 23
* rxdelay: - how long (milliseconds) to delay received data if the
interface is not ready. Increase this value if you encounter
overrun errors in the DOSBox Status Window. Default: 100
* txdelay: - how long to gather data before sending a packet. Default: 12
(reduces Network overhead)
* server: - This nullmodem will be a client connecting to the specified
server. (No server argument: be a server.)
* transparent:1 - Only send the serial data, no RTS/DTR handshake. Use this
when connecting to anything other than a nullmodem.
* telnet:1 - Interpret Telnet data from the remote site. Automatically
sets transparent.
* usedtr:1 - The connection will not be established until DTR is switched
on by the DOS program. Useful for modem terminals.
Automatically sets transparent.
* inhsocket:1 - Use a socket passed to DOSBox by command line. Automatically
sets transparent. (Socket Inheritance: It is used for
playing old DOS door games on new BBS software.)
Example: Be a server listening on TCP port 5000.
serial1=nullmodem server: port:5000 rxdelay:1000