in the U.S., and soon in Canada as well. This system would use frequency division multiplexing to carry 36 voice channels across a series of selected frequencies. On November 4, 1952, Bell gave the DDP their initial proposal.

The next day they learned that the PPO was already well along the process of accepting the ADCOM-like system being proposed by the CSRDE. This used two separate frequencies, one at 2.0 GHz and another at 400 MHz, to allow switching between the two