Techie19 wrote: » Hello all. I have a question pertaining to CSD/DSU devices. On the field I've seen them being used in the Caribbean island airports we support as standalone devices. But here in the states I have not. In the states the T1 lines coming from the smart jack connect directly to the router's T1 WIC port. On this port on the Cisco routers its labeled as T1 CSU/DSU. Just wondering why are CSU/DSU devices used over there as standalone devices and here I haven't seen them? Could it be a requirement from SITA, the company that provides our circuits at there Caribbean locations?