Mitigation method The following definitive mitigation methods were applied: 1) An insulated conduction sheet was pasted onto the circuit board and a capacitor was put between the GND of the circuit and the sheet (Figure 1.4-5). 2) A ferrite bead was installed at the base of Xtal4 (Figure 1.4-6). 3) A capacitor was installed between VCC and GND of IC8 (Figure 1.4-7). 4) Ferrite cores were installed on all lines (Figure 1.4-8). GND Ferrite bead Miti(08)_F1.4-5 Miti(08)_F1.4-6 Xtal4 Insulated conduction sheet Figure 1.4-5 – Conduction sheet Figure 1.4-6 – Ferrite bead International telecommunications line Telecommunication line Mains power line Miti(08)_F1.4-8 Miti(08)_F1.4-7 Figure 1.4-7 – Capacitor Figure 1.4-8 – Ferrite core NOTE 1 – System integrity must be confirmed. NOTE 2 – Changes to the system must be reported to the customer and are outside the guarantee in the future. – 3 – Case study 1.4