Digium 1TE435BF 4 Span Digital T1/E1/J1/PRI PCI-Express X1 Card and Hardware Echo Cancellation 1 Year Warranty Hardware echo cancellation Industry standard RJ-45 port Protocol support includes: ISDN PRI, Robbed-Bit, CAS Supports T1, E1 and J1 physical interface connections, Optional 128ms hardware echo cancellation module