The whole functionality of computers (and software in general) is based on binary system. Everything is "translated" in low-level as 0 and 1 bits.
When coming inside the field of networks, where data are transmitted through physical means, the range 0-2 volts represents bit 0, while the range of 3-5 volts represents bit 1. So, in theory, the digital signal consists of 2 possible values 0 and 5 volts that correspond to bits 0 and 1.
After investigating some network protocols (such as Ethernet) that are using carrier sense, I found out that the channel is "listened" and if no other node is not transmitting, the transmission begins. However, there could be nodes transmitting 0 bits during this specific moment, that could not be detected. For this reason, the carrier sense is being executed for a sequence of 96 bits, and if both bits were 0 then, this is accepted as a fact that no one is transmitting.
THE QUESTION :
If (for example) the selected signals were 5 volts for 0 bit, and 10 volts for 1 bit, then there could be a significant performance boost in those protocols, that could complete the carrier sense in only 1 bit duration (1/96 of the current needed time). Is that true, and if yes, then why wasn't that considered from the beginning as a solution ?
The only reason I know, behind the choice of 0 volts, is that 0 volts correspond to ground, which is a reliable absolute scale.