If supply voltage less then 2*1.4+43~46V zener diodes D17-D120 will be closed, LEDs no light.
If one of lines lost connection LEDs attached to this line will no light.
If polarity on lines 4 and 8 is normal, will light D1 (green) and D8 (red), if the opposite will light D2(red), and D7(green).
hi,
I'm not sure your tester will work as a poe switch is intelligent
it only send the 48v supply if the poe device replies a certain sequence. the 48v are not always present on the wires.
hi,
I'm not sure your tester will work as a poe switch is intelligent
it only send the 48v supply if the poe device replies a certain sequence. the 48v are not always present on the wires.
Yes, my fault. But in IEEE 802.3af PSE is very simple mechanism of classification.
To determine whether a PD is connected, the following input parameters are checked:
• characteristic resistance = RGOOD (19k − 26, 5k),
• typical resistance value = RTY P (25k),
• characteristic capacitance = CGOOD (max.150nF).
This method is called "Resistive Power Discovery".
PD rejection criteria
• resistance less than or equal RBADmin (<= 15k) or
• resistance greater than or equal RBADmax (>= 33k) or
• capacitance greater than or equal CBADmin (>= 10μF)