Description The M-250 is a two line (2-pair) in-line modular filter designed to attenuate radio frequency noise on telephone lines from 75 kHz to 150 MHz. Significant RFI noise can be attributed to florescent lighting, large motors and improper wiring. RFI can also be caused when the subscriber is located near a radio station or other transmitting tower. This filter requires no power or grounding and is balanced to 600 ohms with an off-hook insertion loss of less than 0.1 dB at 1004 Hz. This filter can be used on all telephony applications served from a Central Office or derived locally from a Digital Subscriber Line. The M-250 is a modular device which can be installed at a RJ-14 modular jack near the NID or Residential Gateway to filter both lines of the entire residence without any special wiring or extra connections. NOTE: The M-250 filter is not a "DSL filter" and should be only installed after a DSL master splitter or microfilter.