I know this is slightly off topic, so anticipated apologies:

Is there anyone out there who tried to do do a - *PROLONGATED* -
ser-to-ser connection using a modem on both ser ports connecting then
the 2 modems with an rj11 phone cable? I thought that might be a cheaper
way to exceed the about 5m limit of direct ser connection (at least
that's what I learned would be the limit on the Mac) than any
ser-to-ethernet converter - considering the actual modem prices.

Any idea and suggestions are highly welcome.

Regards, Ulrich