TL-SG105E v5 connected to TL-SG105E v4 fails to negotiate 1000MF
I've been using TL-SG105E v4 devices for quite some time and I am very satisfied.
I recently bought a new unit that's hardware v5. I needed to make an uplink connection between an existing v4 unit and this new v5 unit. The problem is that the uplink can only operate at maximum 100MF instead of 1000MF.
The cable is about 18 meters long and I have a PC (NIC is Intel I219-V if that matters) that connects without a problem to the v4 unit over this same cable at 1000MF. When I connect the v5 switch instead of the PC however, the auto negotiation takes longer than usual (may be about 5-6 seconds) and then sets the connection on 100MF. I tried setting both port (on the v4 switch side) and on the v5 side manually to 1000MF, but in this case the ports LED stay dark and there is no connection.
When I connect the same two switches with a shorted cable, the connection is established very fast at 1000MF.
I believe the problem comes from the "Green" energy-saving feature that is supported by both v4 and v5 switches. Somehow, I guess the power is reduced too much and the switches get to only negotiate stable 100MF connection but fail to do so for 1000MF. The v4 unit's power adapter is rated at 9V 0.6A and the v5 unit has 5V/0.6A adapter, e.g. nearly twice less powerful.
I presume the cable may not be perfect (its not crimped by me, but a commercial product, clamped machinely), but the connection works fine when using a different device (my LAN's NIC). I also tested connecting to the v4 switch another TP-Link device's switch (TL-WR1043ND) and it also negotiates properly 1000MF. I can't change this particular cable, because it is emeded in a channel under the floor and not possible to replace it at the moment.
Do you know of such problem and what else besides the energy saving can explain it?
Is it possible to disable the enegrgy saving on the v4 and/or v5 device?