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Appendix A Quatech Freedom USB Adapter User’s Manual
Appendix A
Specifications
Bus interface USB Specification 1.1
Data rates Number of
simultaneously
operating ports
1-, 2-, 3-port
adapters
(232 and 422)
8-, 16-port
adapters
(232 and 422)
1, 2 230k bps* 230k bps
3, 4 115k bps 115k bps
5+ N/A 57 – 115k bps
* 460.8k bps possible for any one port under
certain conditions
Actual baud rates depend on the following:
Hardware flow control
Horsepower of the host computer
Quality of and length of cables
Continuous or “bursty” data
Ports SSU-100: 1
DSU-100: 2
QSU-100: 4
ESU-100 8
HSU-100 16
DSU-200/300: 2
QSU-200/300: 4
ESU-200/300 8
HSU-200/300 16
UARTs One 16650 UART with 16-byte FIFO per port
Transceivers:
(SP211HB or equivalent)
SSU-100
DSU-100
QSU-100
ESU-100
HSU-100
RS-232 Output
Voltage Swing: +/–5V min, +/–7V typical
RS-232 Input
Voltage Range: –15V min, +15V max
Input Threshold Low: 0.8V min, 1.2V typical
Input Threshold High: 2.4V max, 1.7V typical
Transceivers:
(MAX491 or equivalent)
DSU-200/300
QSU-200/300
ESU-200/300
HSU-200/300
Differential Driver Output (50Ω Load): +2V min
Differential Driver Output (27Ω Load): +1.5V min
+5V max
High Input: +2V min
Low Input: +0.8V max
Driver Rise or Fall Time:
5ns min, 15 ns typ, 25ns max
Driver Input to Output Delay:
10 ns min, 30 ns typ, 60ns max
Receiver Input to Output Delay:
20 ns min, 90ns typ, 150ns max
Page 48 Rev 2.02 (2/24/2004)