The A/B, A/B/C, or A/B/C/D switch within an IP-based VTC system supporting conferences on multiple networks having different classification levels must be based on optical technologies to maintain electrical isolation between the various networks to which it connects.

The A/B, A/B/C, or A/B/C/D switch is physically connected to multiple networks having different classification levels. Copper-based switches provide minimal or no electrical isolation due to capacitance between the wires in the switch box and the switch contacts. This can permit information on one network to bleed or leak over to the other network, which can lead to the disclosure of classified information on a classified network to a network of lower classification. This must be prevented. Optical fiber is an insulator, thus it carries no electrical current and generates no electromagnetic field, eliminating the capacitance issue. As such, it provides excellent electrical isolation between the networks to which it connects.