Two Polycom Phones on One Ethernet Port

[Anonymous]

I am trying to connect two Polycom phones to a single Ethernet port and having issues getting them to connect.  I have a PoE switch supplying power to the first phone, and a power injector powering the second phone.  The cabling looks like this:

Ethernet Switch -- VVX 500 -- Power Injector -- VVX 310

The phone directly connected to the Ethernet Switch works perfectly.  The second phone will not see a network connection.  If I look in the status of the first phone, it shows the PC Port as Inactive.  The second phone reports the LAN Port as Inactive.  I have connected a laptop to the PC Port on the first phone and it works perfectly.  I have swapped the phones and the behavior doesn't follow the phone - the first phone in the chain always works, the second phone never works.

Is there something that I'm missing here?  Why can I not connect a second phone to the PC Port on the first phone like any other Ethernet device?

[SteffenBaierUK]

Hello Eric Hill,

welcome to the Polycom Community.

Do I understand you correctly that you wire the second phone via the PC port of the first phone?

This is post likely the Power Injector only be set for 100FD and the phone tries to negotiate the 1000FD from it's Gigabit switch.

You could attempt to manually change the phone to 100FD and test this then.

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

[Anonymous]

I changed the PC Port of the VVX 500 from Auto to 100FD, and changed the LAN Port of the VVX 310 from Auto to 100FD.  Both phones still report Inactive on the port.

To confirm, the connections are:

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (IN) PoE Injector (OUT) -- (LAN Port) VVX 310

I have confirmed that a laptop and Fluke MicroScanner connected to the OUT port on the PoE Injector will activate and receive a DHCP address.

[Anonymous]

I also just confirmed that the power injector works using this configuration:

Non-PoE Switch (Port 6) -- (IN) PoE Injector (OUT) -- (LAN Port) VVX 310

The VVX 310 received an IP address and linked with the phone server.

[Anonymous · Accepted solution]

I can't explain this, but here's what I found out...

This fails:

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (IN) PoE Injector (OUT) -- (LAN Port) VVX 310

PoE Switch (Port 23) -- (LAN Port) VVX 310 (PC Port) -- (IN) PoE Injector (OUT) -- (LAN Port) VVX 500

This works:

Ethernet Switch (Port 23) -- (IN) PoE Injector (OUT) -- (LAN Port) VVX 500 (PC Port) -- (LAN) Computer

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (LAN) Computer

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (IN) PoE Injector (OUT) -- (LAN) Computer

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (LAN) Fluke

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (IN) PoE Injector (OUT) -- (LAN) Fluke

And now that I have a 48V power supply directly powering the phone, this works:

PoE Switch (Port 23) -- (LAN Port) VVX 500 (PC Port) -- (LAN Port) VVX 310 (48V Power)

Someone with a higher paygrade is going to have to explain that one to me.  Every component works by itself, but when strung together, the PoE injector between two phones causes them both to not see an Ethernet cable between them.  Powering the phone via external 48V works just as expected.