Q & A on Ethernet and Carrier Frequency Q: Since Ethernet is based on CSMA, do you or anyone else know what the carrier frequency is? Does anyone know how a digital data signal(eg. 10 Mbps data signal in the case of 10BaseT) is modulated in the carrier frequency, which I suspect is an anolog signal at a much higher frequency ? A: Ethernet does *not* use a high frequency carrier. It's a baseband network that uses Manchester encoding. In fact, that's what makes it possible to mutliplex mutliple Ethernets over a broadband network -- each Ethernet signal can be used to modulate one particular high-frequency carrier of the broadband system.