Quatech Asynchronous Communications Adapter QSCLP-100 User Manual

Page 24

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4800

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.

QSCLP-100 User's Manual

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