Several people kindly responded to my head-banged-against-a-brick-wall plea for help on getting a DS-3 to work between two cisco PA-2-T3 cards, where the carrier chose to provide this over a CESM interface. Just in case anyone else has to suffer this, here's the useful data I found. The framing (i.e. low level DS-3 framing - *NOT* ATM cell framing) which as I understand it is pretty much the line encoding, operates between the your CPE and the CESM interface at each end. Thus, unlike a "raw" T3, the carrier has to be aware of your line coding. Other than that, they are identical. And for the puzzled - at one end there was a miswire between our router and the telco DDF. Our TX was correctly connected, but our RX was connected to an arbitrary other port with a different type of framing selected on the CESM card. Hence we saw LOF. And the loop tests we asked from 5000 miles away to be applied, were, um, not performed entirely compatibly with scientific method. And yes, it does seem to work (or at least has done for a few hours). Thanks once again for everyone's help. -- Alex Bligh GX Networks (formerly Xara Networks)