Designed specifically for call centers and enterprises. The Blackwire 3220 USB Type-A Corded Stereo UC Headset from Plantronic works with Windows platform and USB devices.. One of the best headset for small budget.
List of products by brand Digium
The 1A4B03F belong to Digium family of A4 Series. This card can be installed in server PCI-Express slot. This card has built in Echo Cancellation
Digium Quad Span Digital T1/E1/J1/PRI PCI-Express x1 Card (1TE435BF) with Hardware Echo Cancellation (VPM128)
Digium 4 Port E1/T1 digital asterisk card 1TE435BF supports up to 120 concurrent calls ideal for large call center. This card works out of the box with any asterisk version.