Grand Junction invented the 100BT ethernet standard, and was the first company to ship 100 megabit ethernet switches. This particular model was a minor variation on the very first. The 24 ports across the bottom are older 10 megabit ethernet, and only support one MAC address apiece (ie: only a computer, not a hub or switch). Two ports all the way on the right suport 100 megabit connections with multiple MAC addresses. The 10 megabit port on the right allows multiple MACs, as well as several types of ethernet connector (10BT, thinwire, and AUI).
Grand Junction were quickly bought out by Cisco, and the FastSwitch was rebadged and sold as a Cisco Catalyst.