21
ASYNC MP LINE DRIVER CARD
Appendix A: Recommended Cable
The Async MP Line Driver Card operates at frequencies of 100 kHz. We’ve
performance-tested it using twisted-pair cable with the following characteristics
described in
Table A-1
.
Table A-1. Cable Characteristics.
Wire Gauge
Capacitance
Resistance
19 AWG
83 nf/mi or 15.72 pf/ft.
0.0163 W/ft.
22 AWG
83 nf/mi or 15.72 pf/ft.
0.0326 W/ft.
24 AWG
83 nf/mi or 15.72 pf/ft.
0.05165 W/ft.
Using or simulating cable with the characteristics described in
Table A-1
, we
obtained the data rate/distance results described in
Table A-2
.
Table A-2. Cable Results.
Data Rate (bps) Gauge (AWG)/Distance (mi)
19
22
24
57,600
2.5
1.8
1.3
38,400
3.7
2.3
1.7
19,200
5.1
3.4
2.4
9,600
6.7
4.6
3.7
4,800
9.4
6.6
5.3
2,400
11.5
9.3
7.6
1,200
14.0
12.0
9.6
To gain optimum performance from the Card, keep the following guidelines in
mind:
•
Always
use twisted-pair wire—this is not an option.
• Use twisted-pair wire with a capacitance of 20 pf/ft. or less.
• Avoid twisted-pair wire thinner than 26 AWG (avoid higher AWG numbers
than 26).
• Using twisted pair with a resistance greater than that described in
Table A-1
may reduce the maximum distance you can obtain. However, the Line Drivers
will still work.
