Document 153 RS-232 EMI Filter Modules Coilcraft’s EMI filter modules are an easy, effective way to eliminate the problems of stray electromagnetic interference (EMI) in signal cables running between poorly filtered equipment. Available in DB-25, -15 and -9 versions, the modules plug between an RS-232 cable and an input or output port. Common mode magnetics filter all lines including the frame ground, attenuating EMI over the critical 30 - 300 MHz range while leaving data signals totally undisturbed. Comparable EMI filters for circuit board mounting are also available. Male DB A B C Pins DLFC9 1.35 34,29 2.25 57,15 0.67 17,02 9 DLFC15 1.65 41,91 2.25 57,15 0.67 17,02 15 DLFC25 2.16 54,86 2.25 57,15 0.67 17,02 25 Female DB A B C Typical Attenuation1 Attenuation (dB) -10 Differential Mode 0 Co mm 10 on Mo de 20 30 0.1 1 10 100 1000 Frequency (MHz) 1. Measured on HP 8753D network analyzer. Ref: 50 Ohms. 2. Operating temperature range –40°C to +85°C. 3. Electrical specifications at 25°C. Specifications subject to change without notice. © Coilcraft, Inc. 2009 Document 153 Revised 11/26/02