Again, benjgvps: both methods get you a command prompt. It all depends on if you want to use Ethernet or serial cable.
If Ethernet (which means your PB150 would need some form of Ethernet,) then SSH is fine.
If serial (which would mean that your FreeNAS needs to have a serial port,) then you need a serial terminal (such as ZTerm.) The fact that you are using an older PowerBook means that I would keep the baud rate at 9600. (Fast enough for a command line.) In pee-air's examples, the number shows the baud rate. (His show both 9600 and 38400.) The parity, bits per character, and stop bit (the "N, 8, 1" parts I mention,) should be set at no parity, 8 bits per character, and 1 stop bit, (again, "N, 8, 1") by default on a modern BSD machine.
All you'll need to specify on the BSD machine is baud rate. And in ZTerm on the PowerBook, make sure you specify the same baud rate.
If Ethernet (which means your PB150 would need some form of Ethernet,) then SSH is fine.
If serial (which would mean that your FreeNAS needs to have a serial port,) then you need a serial terminal (such as ZTerm.) The fact that you are using an older PowerBook means that I would keep the baud rate at 9600. (Fast enough for a command line.) In pee-air's examples, the number shows the baud rate. (His show both 9600 and 38400.) The parity, bits per character, and stop bit (the "N, 8, 1" parts I mention,) should be set at no parity, 8 bits per character, and 1 stop bit, (again, "N, 8, 1") by default on a modern BSD machine.
All you'll need to specify on the BSD machine is baud rate. And in ZTerm on the PowerBook, make sure you specify the same baud rate.