Technology Bit Rate Overhead
| Technology | Rate | Rate ex. Overhead | Year |
|---|---|---|---|
| Morse code (skilled operator) | 0.021 kbit/s | 4 characters per second (~40 wpm) | 1844 |
| Normal Human Speech | 0.039 kbit/s | prehistoric | |
| Teleprinter (50 baud) | 0.05 kbit/s | 404 operations per minute | 1940x |
| Modem 110 baud (Bell 101) | 0.11 kbit/s | 0.010 kB/s (~10 cps) | 1959 |
| Modem 300 (300 baud; Bell 103 or V.21) | 0.3 kbit/s | 0.03 kB/s (~30 cps) | 1962 |
| Modem 1200/75 (600 baud; V.23) | 1.2/0.075 kbit/s | 0.12/0.0075 kB/s (~120 cps) | 1964 |
| Modem 1200 (600 baud; Vadic VA3400, Bell 212A, or V.22) | 1.2 kbit/s | 0.12 kB/s (~120 cps) | 1976 |
| Modem 1200 (Bell 202C, 202D) | 1.2 kbit/s | 0.15 kB/s (~150 cps) | |
| Modem 2000 (Bell 201A) | 2 kbit/s | 0.25 kB/s (~250 cps) | |
| Modem 2400 (Bell 201B) | 2.4 kbit/s | 0.3 kB/s (~300 cps) | |
| Modem 2400 (600 baud; V.22bis) | 2.4 kbit/s | 0.3 kB/s | 1984 |
| Modem 4800/75 (1600 baud; V.27ter) | 4.8/0.075 kbit/s | 0.6/0.0075 kB/s | 1976 |
| Modem 4800 (1600 baud, Bell 208A, 208B) | 4.8 kbit/s | 0.6 kB/s | |
| Modem 9600 (2400 baud; V.32) | 9.6 kbit/s | 1.2 kB/s | 1984 |
| Modem 14.4 (2400 baud; V.32bis) | 14.4 kbit/s | 1.8 kB/s | 1991 |
| Modem 28.8 (3200 baud; V.34-1994) | 28.8 kbit/s | 3.6 kB/s | 1994 |
| Modem 33.6 (3429 baud; V.34-1996/98) | 33.6 kbit/s | 4.2 kB/s | 1996 |
| Modem 56k (8000/3429 baud; V.90) | 56.0/33.6 kbit/s | 7/4.2 kB/s | 1998 |
| Modem 56k (8000/8000 baud; V.92) | 56.0/48.0 kbit/s | 7/6 kB/s | 2001 |
| Modem data compression (variable; V.92/V.44) | 56.0–320.0 kbit/s | 7–40 kB/s | 2000 |
| ISP-side text/image compression (variable) | 56.0–1000.0 kbit/s | 7–125 kB/s | 1998 |
| ISDN Basic Rate Interface (single/dual channel) | 64/128 kbit/s | 8/16 kB/s | 1986 |
| IDSL (dual ISDN + 16 kbit/s data channels) | 144 kbit/s | 18 kB/s | 2000 |