USE OF 64 KBPS BANDWIDTH FOR VOICE AND DATA COMMUNICATIONS

It all started with the decision to make phone calls at 64Kbps. When a conversation takes place between two telephones, the sound is not completely transmitted to the other party as it is, it is sampled and downsampled. The human ear doesn’t notice the downscaling, in fact certain parts of our conversations are transmitted over the phone.

This minimization process is done as follows, 8000 samples of the human voice are taken per second and each sample is expressed in 8 bits, as a result, the human voice is sent to the other side with 8000 x 8 bits per second, in other words 64000 bits. This is where the 64Kbps concept comes from.

The old analog modems offered an information carrying capacity of 56Kbps, in fact these modems are 64Kbps, but since data is carried over these modems instead of voice, telecom operators have reserved one of the 8 bits in each sample for themselves, so analog modems are connected to the internet at 8000 x 7 bits, 56000b per second.