Product Content CL-FOM400 4E1 Standalon PDH Multiplexer. CL-FOM401 4E1 19′ PDH Multiplexer. CL-FOM801 8E1 19′ PDH Multiplexer. CL-FOM1600 16E1 19′ PDH Multiplexer TDM(E1) over Fiber. Description Overview: CL-FOM400, 401,801, 1600 4,8,16E1 PDH (Plesiochronous Digital Hierarchy) which was used in exchanger for long distance transmission, and platform of mobile telecommunication, pager