OpenVox AE2410P takes full advantage of Octasic® Hardware Echo Cancellation Module to deliver the superior voice quality on both FXO and FXS interfaces in all 24 ports.Adjustable Interrupt Routing Design Interrupts frequency adjustment Up to 24 Simultaneous PSTN Calls (Per PCI Slot) Compatible with All Commercially Available Motherboards Octasic Hardware Echo Cancellation Module Available.