SIP-T43U causing pc to lose network connection

[itbioveld]

We have recently installed several SIP-T43U phones. We were connecting them by connecting the network cable from a POE wall outlet(switch) to the phone and then connecting the phone cable to the pc. This works for a while - sometimes months - but then the pc starts losing network connection intermittently. The fix has been to connect both the pc and the phone separately to a non -POE switch and then connecting the AC adapter to supply power to the phone. I also tried connecting the pc and the phone separately to a POE switch and found that after a week or two the pc had intermittent network connection loss. The only fix seems to be to install and connect to a non-POE switch and use an AC adapter. However, one of the AC adapters has died and I have no replacement so I have one phone that is not operational. I need a solution so that I can use the phone again with a POE connection.
We would prefer just to use the original(normal) method of connecting the network cable to the phone and then connecting the pc to the phone. Is there something that I can check or configure that will fix this problem? Is there a firmware fix for the phone that will fix the problem? Thanks.

[complex1]

(05-07-2021 11:28 PM)itbioveld Wrote:  We have recently installed several SIP-T43U phones. We were connecting them by connecting the network cable from a POE wall outlet(switch) to the phone and then connecting the phone cable to the pc. This works for a while - sometimes months - but then the pc starts losing network connection intermittently. The fix has been to connect both the pc and the phone separately to a non -POE switch and then connecting the AC adapter to supply power to the phone. I also tried connecting the pc and the phone separately to a POE switch and found that after a week or two the pc had intermittent network connection loss. The only fix seems to be to install and connect to a non-POE switch and use an AC adapter. However, one of the AC adapters has died and I have no replacement so I have one phone that is not operational. I need a solution so that I can use the phone again with a POE connection.
We would prefer just to use the original(normal) method of connecting the network cable to the phone and then connecting the pc to the phone. Is there something that I can check or configure that will fix this problem? Is there a firmware fix for the phone that will fix the problem? Thanks.

Hi,

If the phone works well with a separate power adapter, then it makes no sense to fix the firmware.

Make sure that the PoE switch can supply enough power and that the wires in the network cable between switch and phone are made of 100% copper and not an alloy.
Use an 802.3at PoE switch and CAT5E or better cable.

[itbioveld]

Hi,

If the phone works well with a separate power adapter, then it makes no sense to fix the firmware.

Make sure that the PoE switch can supply enough power and that the wires in the network cable between switch and phone are made of 100% copper and not an alloy.
Use an 802.3at PoE switch and CAT5E or better cable.
[/quote]

Thanks for the reply.
We are using the cable that came with the phone. If the manufacturer provided it, it should be sufficient.
The switches are new and should be supplying enough power. The phone requires 5 volts, 1200ma and the switch is rated at 48vdc, 30 watts. Are you saying that if the power demand on the switch is high, it will disrupt the network communication on the pc?
Using the phone with the AC adapter works when I have an adapter. Unfortunately we had some adapters go missing and now I have a phone without any adapter. Also, I'm finding that I have to install an non-POE switch because I am connecting two lines(one from pc and one from the phone) to my network. I haven't tried using the AC adapter with the single line(network to phone, phone to PC) approach. Because the phone was interfering with the pc, I assumed that it should have a separate connection to the network).

[stratos]

How many phones are plugged into the POE switch?