Originally posted by: Loki726
Its also interesting to note that you can put several different signals on the same line as long as they are sent at different frequencies and filtered out appropriately. ie DSL
Originally posted by: onix
So you're saying that when I talk, I hear myself just as loudly as the person talking to me, or perhaps even louder?
Originally posted by: Loki726
Its also interesting to note that you can put several different signals on the same line as long as they are sent at different frequencies and filtered out appropriately. ie DSL
Originally posted by: The Boston Dangler
Originally posted by: Loki726
Its also interesting to note that you can put several different signals on the same line as long as they are sent at different frequencies and filtered out appropriately. ie DSL
It's not just phones and cable tv. The FCC frequency allocation chart in my office covers up to 300 GHz. This is over-the-air. Like 100 different services, all these carriers at the same time.
Sadly, most of this was given away freely to major industial players, courtesy of a very corporate-friendly FCC. Huge companies make out of control profits from this bandwidth, and what did the US taxpayers get for their property? Well, I got a $55 cell phone bill every month.
Any wired service can run any frequencies they want to, as long as it stays inside the wire.
Originally posted by: shortylickens
Since I work in communications, I think I'll shed a little light on this subject.
We these items called Multiplexers. They split signals up and mix and match them with different inputs and outputs.
One millisecond you are recieving, next you are sending. (It could be 2 milliseconds or 1/2 a millisecond or whatever). This can be done with digital or analog signals, although most technology has been pushing for better digital multiplexers.
This makes it seem as if you were talking and listening at the same time. (Full Duplex)
In reality to get full duplex you would need two seperate comm circuits.
Like in radio you would need to have a reciever and transmitter each with their own freq.
The guy on the other end would have the same thing but reversed. You would also need two antennas. Its much simpler to just have the thing always in recieve mode except when talking (Half Duplex). Then you just need a little mike discipline.
Multiplexers allow us to have really complex comm circuits running on just one microwave transceiver, to give one example.
In fact the FRC-173 is a microwave transceiver, multiplexer and router all in a single unit.