Quatech USB-to-Serial Adapter User’s Manual
Appendix A
Appendix A
Specifications
Bus interface
USB Specification 2.0, high speed 480 Mbps.
Backward compatible with USB 1.1 full speed 12
Mbps.
Baud rates
Up to 921,600 bps.
Factors impacting performance include:
¾
Hardware flow control
¾
Horsepower of the host computer
¾
Quality of and length of cables
¾
Continuous or “bursty” data
Ports SSU2-100:
1
DSU2-100:
2
QSU2-100:
4
ESU2-100
8
DSU2-400:
2
QSU2-400:
4
ESU2-400
8
UARTs
SSU2-100:
16550 UART with 1024-byte
secondary FIFO buffering for both
transmit and receive.
All others:
Custom high-speed UARTs with
1024-byte FIFOs for both transmit
and receive. Automatic hardware
and software flow control.
Transceivers:
SSU2-100
DSU2-100
QSU2-100
ESU2-100
RS-232 Output
Voltage Swing: +/–5V min, +/–5.4V typical
RS-232 Input
Voltage Range: –15V min, +15V max
Input Threshold Low: 0.6V min, 1.0V typical
Input Threshold High: 2.4V max, 1.5V typical
Transceivers:
DSU2-400
QSU2-400
ESU2-400
RS-232, see above.
RS-422/485:
Differential Driver Output (50
Ω
Load): +2V min
+3.3V max
Differential Driver Output (27
Ω
Load): +1.5V min
+3.3V max
High Input: +2V min
Low Input: +0.8V max
Driver Rise or Fall Time:
5 ns typ, 20.5 ns max
Driver Input to Output Delay:
20 ns min, 40 ns typ, 60ns max
Receiver Input to Output Delay:
40 ns min, 70 ns typ, 100 ns max
Rev 1.01 (February 2007)
Page 25
