We have a customer with Definity G3si R10 that had an EPN working over multimode fiber direct connect. They closed the office where the EPN was and it is hooked up in the switch room by a mm fiber patch cord to the PPN and working fine. They are relocating the EPN to a new remote office that is connected by Single Mode fiber. To try to make sure the system will work OK I tried to hook the EPN to the PPN with 300a single mode transceivers and single mode patch cords. I have inserted a 10db 1310nm attenuator but can not get the EPN to come up.I made sure the fibers are reversed. (tried both ways). I have tn570c expansion modules in each cabinet. Does anyone have any ideas? This is an offer B if it matters.