Configuring M3SE MAC Address
The M3SE requires an Ethernet hardware address, known as its MAC (Media Access Controller) address. This address consists of six hexadecimal bytes separated by colons. It is configured in the hardware section of the NETWORK/CFG file:
[Hardware] # Bit 1 of 1st byte set -> locally administered address # Other 5 bytes can be anything locally unique MAC Address = 02:00:00:00:00:03
As shipped, the M3SE uses a locally-administered MAC address, which is indicated by setting the second least significant bit of the first byte. This address must be unique on your local network. If you wish to continue using a locally-administered MAC address and the one supplied is not unique, simply modify the file so that it is.
If you wish to use a globally-unique MAC address, the GETMAC utility will display the address assigned to your M3SE. Enter this address into the NETWORK/CFG file. This step is normally not necessary if you have a home router, which replaces the MAC addresses of devices on your local network with its own before sending packets to your Internet Service Provider. If, however, you have the temerity and capability to attach your TRS-80 directly to the Internet, you might need the globally-unique address.
Either way, the MAC address is read, and the Ethernet module is configured, by the DHCP/CMD utility. This applies whether or not you have a DHCP server. See the section on setting your IP address for details.