Improved arrangement for interfacing between a Digital Subscriber Line (DSL), and a telephone network and data network. A Low-Pass Filter is mounted together with a POTS (Plain Old Telephone Service) interface circuit to reduce the number of connections to a Main Distributing Frame (MDF). Other arrangements are disclosed for mounting blocking capacitors to isolate a data network test access from the POTS service provision. Advantageously, reliable DSL service is provided at lower operations and apparatus cost.