You want www.unna.org , as an earlier post said.
There was no internal modem, because the MP was made to use PCMCIA expansion cards. The square cover you mention is more or less irrelevant, as nothing was actually manufactured back in the day to go in there, unless you want to go the way of hardware hacking and install, say, a serial/ localtalk port (it can be done). Since it was designed to use PCMCIA cards, it is to be expected that a great many PCMCIA modem/ fax cards will work perfectly well in a MP2000, but you have to have the system set up right for one of them, and some cards will likely work with the thing better than others.
The Preferences pane has some modem settings that can be tinkered with, and there is a modem modifier program (try unna) that will allow you to tweak some more if it comes to that, or if you want to use something that the machine doesn't like.
I have long experience of the Newton platform, but so many around here do not that it is almost a waste of time asking anything. The best place to ask questions is the Newtontalk list, which also has a searchable archive.
There was no internal modem, because the MP was made to use PCMCIA expansion cards. The square cover you mention is more or less irrelevant, as nothing was actually manufactured back in the day to go in there, unless you want to go the way of hardware hacking and install, say, a serial/ localtalk port (it can be done). Since it was designed to use PCMCIA cards, it is to be expected that a great many PCMCIA modem/ fax cards will work perfectly well in a MP2000, but you have to have the system set up right for one of them, and some cards will likely work with the thing better than others.
The Preferences pane has some modem settings that can be tinkered with, and there is a modem modifier program (try unna) that will allow you to tweak some more if it comes to that, or if you want to use something that the machine doesn't like.
I have long experience of the Newton platform, but so many around here do not that it is almost a waste of time asking anything. The best place to ask questions is the Newtontalk list, which also has a searchable archive.