New modem for B&W G3

[Michael George]

I've a friend with an old B&W G3 with no modem.  He wants to add one to 
it and asked me how we would do that.  I am not all that well-versed 
with USB for linux (either platform) so I'm not sure if we should scour 
the internet for an internal (if this model can even support it), or if 
a USB modem will work with YDL, or if we should get a USB-->RS232 
adapter and use an external modem...

I'd like the advice of the knowledgeable on the list.  Thanks!

-Michael