Cisco Systems 1-Port T1/Fractional T1 DSU/CSU WAN Interface Card
Cisco (0882658146701 / HWIC-1DSU-T1=)
Cisco (0882658146701 / HWIC-1DSU-T1=)
Ubiquiti (0810354024788 / 505346)
Gembird (8716309062800 / DSU-21) | USB device, Input USB