There are actually 3 important parts: what API you use to build your application, starting the Altia Runtime on the right port and then specifying the machine/port to connect to.
1) USE THE LAN API
First of all, if you are communicating between machines, you must make sure to use the TCP/IP version of the API (not the DDE version) to build the host/controlling application. For example, you would link in [ALTIAHOME]\libfloat\ms32\liblan.lib in your MS Dev Project or Makefile (NOT libdde.lib, which is the default).
2) SPECIFY THE PORT WHEN STARTING RUNTIME
When you start the Altia Runtime on the client, you can pass in a port number on the command line. You can also specify this port number in an AtStartInterface() , but you cannot use AtStartInterface to start a Runtime on another machine. So, you won't use AtStartInterface() on your host machine.
To start an interface with a specific port from the command line, on the client type in something like:
altiart.exe design1.dsn -port :5200
3) SPECIFY THE PORT WHEN OPENING A CONNECTION
Once your runtime is running on the client, you need to open a connection to it. Do this using the AtOpenConnection() function and specifying the same port number as before. For example:
AtOpenConnection("client1:5200", NULL, 0, NULL);
where client1 is the machine name of the client machine.