V.90
I have included V.34 is this discussion because the newer V.90 modem in the fall-back mode uses the V.34 operations on the analog side of the modem. V.90 also uses V.34 modulation in the upstream direction (from user modem to the network).
The V.90 modem, also known as the 56 kbit/s modem, has become the dominant modem technology in the industry. It has the following characteristic:
Operates in full duplex on telephone lines (local loops).
Echo cancellation used for separating channels.
Uses pulse code modulation (PCM) in the downstream direction (from network to user modem) at a symbol rate of 8000.
Downstream data rates range from 28 kbit/s to 56 kbits/s in incriments of 8000/6 bit/s.
V.34 modulation is employed in the upstream direction, ...
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