PTP670 PoE power connection

Products PTP
1

I have a project which has the cnPilot e700 and the PTP670 placed at the same location. May I know if we can connect the PTP670 ODU directly to a standard GBE PoE+ switch ?

If it is possible, it may help to minize the use of the enhanced AC+DC power supply for the PTP670 ODU and the PoE injector for the e700 AP.

2

The below thread was for PTP650, not PTP670, but the same might apply.

http://community.cambiumnetworks.com/t5/PTP-FAQ/PTP-650-Compatibilty-with-802-3at-standard-PoE/m-p/50740#U50740

I think it will depend on the switch. If it has a passive mode that is always providing power on the correct pins, it should work. If it is an active only POE switch, requiring a handshake negotiation before provding power, then it won't work.

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3

We use PTP650's and 670's w/Netonix switches just fine. We use the 48VH port mode.

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4

There are a couple of relevant differences between PTP 650 and PTP 670:

  • The power consumed by PTP 670 is somewhat higher, typically 30 W. A power source equipment (PSE) in IEEE 802.3 Type 2 (also known as 802.3at) must supply at least 30 W, but only 25.5 W is guaranteed at the powered device (PD). The rest is dissipated in cable losses. PoE switches might be able to supply enough power, but this may not always be the case. The situation gets progressively less satisfactory as the cable length increases towards 100 m.
  • PTP 670 can be configured to negotiate the power required using the standard "signature" method. We don't support the LLDP negotiation. The signature-based negotiation is a feature that was not in PTP 650. If your switch has a passive mode, then that remains the most straightforward solution.

Remember that you shouldn't use the PoE output from PTP 670 when the PTP 670 itself is supplied using 802.3at.