I´m using Mac OS 7.5.5 - thanks to a RAM upgrade I´m quite comfortable with that OS on the PB 145b.

Now the solution...

I´m supposing You are using MacTCP (control panel) and NOT TCP/IP that came with 7.5.3... In this case the solution to find the MAC adress of Your adapter is very simple: open the "MacTCP" control panel. At least two icons should appear (if the Asante software is installed): "LocalTalk" and "Ethernet built in" (or similar, I´m using a german OS...). Now hold the "Option" key on Your keyboard an click the "Ethernet built in" once. Below that icon there should now appear the MAC adress. Remember: don´t forget to put a ":" between every two numbers/letters ;-)

J