Openvox FXS402 Dual CH Quad FXS Module for A810 A1610 A2410Overview The FXS402 Dual channels Quad FXS module allows OpenVox Analog A810 A1610 A2410 series cards to terminate four analog telephones per module. Because of the modular design, users can activate additional ports at any time with more modules. The FXS402 module passes all the call features any standard analog telephone line will support. Functions: FXS Foreign Exchange Station FXO Foreign Exchange Office An FXS device initiates and sends ringing