I bought CSS610-8P-2S+IN and CSS610-8G-2S+IN and thought in will be possible to power the G version from P version using DC jacks. I’m powering the P version from the internal power source (from grid). I checked voltage on the jack by multimeter, it was about 53.5V; good, but there is small voltage drop compared to Health tab in management web. OK, I connected both DC jacks to each other switch and it doesn’t work. Because of the voltage drop, I think there is a (protective) diode and is not possible to take power from DC jack on CSS610-8P-2S+IN, right?
CSS610-8G-2S+IN with provided adapter works.
I don’t want to use PoE; switches are connected to each other by 10G fiber link. Bypass the diode possible? Or keep using the (one of many) adapter?
Thanks
The P version of CSS610 should be able to power the G version just fine. G version accepts anything between 12V and 57V on PoE-in, so even with some voltage drop in cables it should be fine. Max rated power consumption of G variant is specced at 11W, even if input voltage would drop to 44V this means up to 0.25A. Which is again well within specced PoE-out capacity of the P variant.
And now the details to look after: G variant PoE-in is declared as passive PoE-in … OTOH G variant can do both passive PoE-out and 802.3 af/at. But proper auto detection of (potential) PoE load in such case is not guaranteed. So on the G variant you may have to explicitly enable PoE out on port which is powering the G variant, setting PoE out to auto may not be OK …
A side question: is the UTP cable, connected to ether1 on G variant, the only connection between both devices?
Thank you. There is no cable connected to G switch Port1 (PoE in). I don’t wish to use PoE (why is explained in my first post - switches are already connected to each other by 10G fiber and don’t want to lose one port on each switch just for PoE).
I attempted to draw power from the DC jack on front side of the P switch and deliver it to the front DC jack of the G switch.
Now I arranged a measurement when both DC jack were connected. Voltage dropped from 53.5 (without load, just multimeter with high impendance) to near zero (when connected to G switch DC-in). It means it’s not possible to draw power from DC jack of the P switch without HW modification, which I’ll not do.; it’s not designed to draw power from this connector a probably the protection diode (which, IMO, protects the switch against reverse polarity) is closed.
So one more AC/DC adapter connected and running
I attempted to draw power from the DC jack on front side of the P switch and deliver it to the front DC jack of the G switch.
No, this is not possible, jacks are power-in-only. They are “protected” by a diode … which also prevents from funny things to happen if multiple power sources are connected (for redundancy) but use different voltages.
If you can spare one ethernet port on P switch and ether1 on G switch, you could use it to power the G switch … it would most probably work as-is, RSTP should disable connectivity over RJ45 connection as long as SFP+ connection is up and running.
