Quatech Asynchronous Communications Adapter for PCI bus DSCLP/SSCLP-100 User Manual page 36

Data Rate
(kbaud)
921.6
460.8
230.4
115.2
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.
36
Maximum Load (pF)
4% 10% 15%
trans trans trans
time time time
N/A 100 300
100 430 670
330 900 1100
800 1570 3300
DSCLP/SSCLP-100 User's Manual
20% 25%
trans trans
time time
430 470
900 1100
1630 2000
4300 4800