The D280 is a simple, low-cost tool for testing Ethernet ports to verify service and advertised capabilities. It’s easy to use and can fit in your pocket or tool kit. Ambiguous duplex and link compatibility issues are quickly resolved with bicolor LEDs, which indicate Hub or NIC, Speed, Duplex and Auto settings for the equipment in question.

Just plug it in! The Speed Reader is activated automatically if it detects Ethernet equipment at the far end of the cable. If the connection is OPEN, then nothing will happen. Likewise, if the port is really for TOKEN RING or is a TELCO circuit, then nothing will happen. When you plug the D280 into an Ethernet device, it will first power up and flash all of its LEDs (both red and green) and then it will indicate the specifics of the Ethernet service as follows: Green LEDs mean that the device looks like a HUB or a SWITCH and the red LEDs mean that the device looks like a NIC card in a COMPUTER or looks like a WAN port on a router. This identification scheme assumes a “straight through” cable with correct polarity like the one supplied with the Speed Reader. If all LEDs remain off, it means that the connection is open, or something other than Ethernet was detected. If your D280 LEDs appear dim or fail to function, it may be time to replace the 9-volt alkaline battery.