I measured 800ms delay between pressing the PTT at Console Input or clicking on TX-Button and Pluto- GPO-Signal. This was confirmed by Evariste, F5OEO. Hew wrote me, this is the round trip of his firmware_031. He wrote also, this can be reduced to some milliseconds but I don't know if this is done already. Meanwhile, I found the POE-Adapter-Solution and it works well and very fast. And was copied by some friends.
To avoid missunderstandings, the delay was not caused by the Console or the method how to activate the transmit mode. Keeping the amplifier in TX-Mode, the delay was very low also. So, the Pluto was ready to transmit but the Amps were switched on and off with 800ms delay. Using the Ethernet-Line is very simple and cheap and there is no distance limit.