4880
4300
3300
1570
800
115.2
2000
1630
1100
900
330
230.4
1100
900
670
430
100
460.8
470
430
300
100
N/A
921.6
25%
trans
time
20%
trans
time
15%
trans
time
10%
trans
time
4%
trans
time
Maximum Load (pF)
Data Rate
(kbaud)
Note 1:
The signal transition time ratio is defined as the percentage of the unit interval or
bit time (the inverse of the data rate) that is occupied by the signal transitioning from -3V
to +3V. The EIA/TIA-232-E standard defines a maximum signal transition time ratio of
4%; most RS-232 receivers will recognize signal transitions with much larger ratios.
With a 4% signal transition time ratio, EIA/TIA-232-E is limited to a theoretical data rate
of 200 kbaud. If maximum signal transition time ratio is extended to 10%, 15%, 20%, or
even 25%, the maximum data rate achievable using EIA/TIA-232-E can be increased past
200 kbaud.
Note 2:
A typical value for capacitance per foot of standard cable is 50 pF/ft.
Quatech DSC-100 User's Manual
34