MS-TestPro
User’s Manual
Page 42 of 113
4.2.4.6
DCR - DC Resistance Testing
Using the MS-TestPro
DCR
and
Looper
modules, you can test the DC resistance of CATx cables, and
check their ability to provide a sufficient level of PoH (Power over HDBaseT) powering.
The DC Resistance module is inserted into the lower slot in the MS-TestPro main unit, while the CATx
cable is connected to the DC Resistance module at one end, and to the Looper module at the other
end, as depicted in the figure below:
Figure 49: DC Resistance Test Setup
➔
To test the DC resistance of a CATx cable:
1.
Attach the cable to the DC Resistance and Looper modules as shown in the figure above.
2.
From the Tools page, tap on the
DCR
button. The DCR page appears, together with three
buttons:
◼
Loop Resistance
◼
Parallel DC Resistance Unbalanced
◼
Pair to Pair Resistance Unbalanced
3.
Tap on the
Loop Resistance
button to display Loop Resistance data, as shown in the figure
below. Loop resistance represents the DC resistance (in ohms) of a single twisted pair in a
cable, and is calculated as the sum of the DC resistance of the two conductors of the
twisted pair.
Resistance of
under 20 ohms
indicates that the pair should be capable of delivering the
minimum of 80% of the power to the remote side.
