Hello,
I buyed several 2M POE IP cams from Dongjia incl. a 8 Port POE NVR Type 2508. As I tested them, I found that the
NVR (with 2 NICs) is not very flexible in the configuration. That means that the forwarding between the 2 NICs is not active
and I cant see the cams behind the NVR from the LAN. The CAMs cannot synchronize the time/date with NTP servers from internet and I want to reconfigurate them any time if necessary without changing IPs.
I decided to use a POE switch connected on just one of the NICs from NVR. The problem is that the cams
are not working (they become no power from switch). I found that the switch is working in mode B (the switch is a high quality, industrial one, 3810G from Korenix) and the cams are working only in mode A.
As I read the standard 802.3af I found that the PSE (the switch) can work in mode A or B (just one of them) but the
PD (powered device, like the cam) must support both modes. If not the PD is not 802.3af compliant...that seems to be with my cams
I opened one cam and found that the RJ-45 is only a 4-wire cable. For mode A is enough. For mode B isn't because the
power supply is coming on 4/5 and 7/8. I found in the cam a small connector which is not wired and is marked with
4/5 7/8...the IC on the POE Board is an AS1138 and I found that this IC is full compliant with 802.3af
The question now is, at first if I may electrically connect the 4/5 and 7/8 from the POE switch to this connector
and the 2nd where could I find such cables or the components like the small connectors to build it.
An answer from you would be very appreciated.
Many thx
Ciprian
I buyed several 2M POE IP cams from Dongjia incl. a 8 Port POE NVR Type 2508. As I tested them, I found that the
NVR (with 2 NICs) is not very flexible in the configuration. That means that the forwarding between the 2 NICs is not active
and I cant see the cams behind the NVR from the LAN. The CAMs cannot synchronize the time/date with NTP servers from internet and I want to reconfigurate them any time if necessary without changing IPs.
I decided to use a POE switch connected on just one of the NICs from NVR. The problem is that the cams
are not working (they become no power from switch). I found that the switch is working in mode B (the switch is a high quality, industrial one, 3810G from Korenix) and the cams are working only in mode A.
As I read the standard 802.3af I found that the PSE (the switch) can work in mode A or B (just one of them) but the
PD (powered device, like the cam) must support both modes. If not the PD is not 802.3af compliant...that seems to be with my cams
I opened one cam and found that the RJ-45 is only a 4-wire cable. For mode A is enough. For mode B isn't because the
power supply is coming on 4/5 and 7/8. I found in the cam a small connector which is not wired and is marked with
4/5 7/8...the IC on the POE Board is an AS1138 and I found that this IC is full compliant with 802.3af
The question now is, at first if I may electrically connect the 4/5 and 7/8 from the POE switch to this connector
and the 2nd where could I find such cables or the components like the small connectors to build it.
An answer from you would be very appreciated.
Many thx
Ciprian