PE automatically selects the port to be used, you cannot change it manually. I guess it's debatable whether or not that would be considered crude. The default is com1, and although PE will use other ports, any lower numbered port would have to be busy for this to occur. See here for a partial explanation: [Link: remotecentral.com].

You could try using Tonto, a 3rd party replacement for PE. It's better at communications and will use any port available, regardless if lower ports are busy or not. Still not manually selectable however. Available here: [Link: giantlaser.com]