Voice Data Transfer

A significant area of concern when handling the transfer of voice data is the data transfer rate on the modem/DTE interface. Data transfer rates can be expressed as the number of interrupts which must be serviced per time period to keep up. This is a function of the sampling rate and compression method (if any) used by the modem, and the DTE interface speed required to handle the data flow on the telephone line side.

7.2 KHZ Sample Rate DTE Speeds

Modem                                                                    



Samples           Required Asynchronous           Implied DTE            


per 8-bit Byte    DTE Speed (8N1 Format)          Speed Supported        


2 (4-bits)        36,000 bits/s                   38.4 kbits/s           


2.66 (3-bits)     27,000 bits/s                   38.4 kbits/s           


4 (2-bits)        18,000 bits/s                   19.2 kbits/s

Note: The current exclusive sampling rate is 7.2 kHz.

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