Since it didn't leave me any peace, I made a tape data cable again.

It actually worked. The band data is transmitted and the ACOM 700S switches the bands immediately.

I have adapted the circuit diagram of Roman again if someone needs it.

Mathias, DD5MD

Hi, Mathias.
In principle, the schematic we offered should work, the control cable must have the stabilitron and a separate resistor in front of four other resistors, it is mandatory.
If you remove them from the schematic it may damage the controller in the PA.

Unfortunately, we don't have an ACOM PA in the office, thus cannot test the schematic we offered and adjust it if necessary.
Please be very careful using the cable which you've created.

Hi Roman,

attached the modified and working schematic with a 510 Ohm (instead of 1 kOhm) resistor before the four other resistors and a 5V Zener diode between pin 14 and pin 15.

I have already recreated and tested the cable. Power on, PTT and band switching work fine.

Kind regards

Mathias, DD5MD