TCS AVN0 outdoor station: no IP?

I have a TCS video outdoor station AVN0. It should be connected to a Fritz box. A POE injector is integrated in the network connection.

Problem: The AVN outdoor station can't be addressed. FritzBox has the IP 192.168.178.1 and offers DHCP. The TCS outstation is said to have the IP 192.168.1.251.

But it is not recognized by the Fritzbox. A network scan does not find them either. It also can't be pinged directly.

Connected directly to the laptop (192.168.1.1), the same. POE works correctly, LEDs light up, LEDs on the network interface flash. MAC address can be read out. But establishing a connection does not work.

Who can help me?

Tried to interpose a switch or assign a fixed IP?

The outdoor station is actually attached to a ProCurve Switch 2610-24 / 12PWR (IP 192.168.178.xxx). POE works, the MAC is displayed correctly when the port is queried on the switch. Pinging not possible. The different network areas were suspected (192.168.178.xxx against 192.168.1.251). A network scan with nmap produced no results.

Therefore, directly connected to the laptop, laptop IP set to 192.168.1.1 manually, network cable connected to the TCS outdoor station and tested by POE injector.

Do not enter the configuration of the TCS outdoor station without a web interface to change the factory IP from 192.168.1.251 (according to the manual) to dhcp or to assign a fixed IP.

Without (current) IP there's no way to change the IP. I turn in a circle.

Hardware reset carried out, should change to 192.168.1.251. But didn't help either.