Scott Ferguson wrote:
The term "balanced" is often confused or mystified by electronic engineers too, but if you drive and receive two wires with equal impedance, and compare the signals to each other and not to (local) GND, that is a balanced transmission.I suspect some of the confusion (in this thread) comes from the difference between an ideal balanced state, and a non-functioning state.
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More importantly - the 'phone system, particularly the outsiders view of it, is not particularly relevant to the "serial connection" cabling question. :-)
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Note: the opinions and experiences of telecommunications technicians, and Complex Data Testers may differ from that of textbooks ;-p
I don't want to go deeper in this flame, since these things are cleary stated in standards and textbooks, the priciples were invented at least one century ago. The opinons doesn't matter, only the physics.
Those who think it's the best idea to transmit RS-232 signals in UTP cables, I recommend further learning in this area. Or if you don't believe in textbooks, just try it! Try unshieled cable, try shielded, wire-by-wire shielded, TP cable, and try the same TP cable with RS485 transceivers (and surprise...) Interconnecting two line-level audio equipment is even more expressive, you obviously will hear the difference!