# + and - meaning in Tx+ and Tx- in cable pairs?

Tx and Rx are required in Computer networking, used in Cat5 or Cat5e or Cat6 cable? What does +(plus) and -(minus) sign mean in cable pairs for RJ45

The positive and negative connectors in the cabling mentioned, form a balanced pair for signals. They typically carry identical signals of opposite polarity, i.e. a HIGH bit may be +5 Volts on the + conductor, and -5 Volts on the - conductor. The corresponding LOW bit would then be -5 Volts on the + conductor, and +5 Volts on the - conductor.