line and between the tip line connection and the voiceband modem interface tip line a series pair of inductors a first inductor of the series pair has a low inductance and a high self resonant frequency and a second inductor of the series pair has a high inductance and low self resonant frequency the low inductance the high self resonant frequency the high inductance and the low self resonant frequency are each determined to locate a filtering cutoff point between the voiceband modem operating frequency band and a digital subscriber line operating frequency band application_number US 60280003 A description 0026 fig2 depicts the typical frequency plans used by voiceband modems hpna and one example of dsl e g adsl over telephone wires such as the system depicted in fig1 e voiceband modems would occupy frequency band 111 300 4000 hz adsl upstream would occupy frequency band 113 26 138 khz adsl downstream would occupy frequency band 115 138 khz 1 104 mhz an hpna implementation such as the broadcom corporation family of iline tm family of controllers would occupy frequency band 117 4 10 mhz generally the dsl service and the voiceband modem will not be used simultaneously however as voiceband modems are used in facsimile transmissions a voiceband modem connection for fax transmission may occur while the dsl service is in use also in some residential applications the dsl service may.