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Line Filter VF

The MOD22014 is a 24 channel VF Line Conditioner for interfacing VF ports on telecommunications equipment to telecoms circuits running in close proximity to the electrified rail infrastructure. The Line Conditioner is designed to be used with the Cisco VG350 voice gateway to offer the performance requirements of NR/L2/TEL/30003. Other variants of the Line Conditioner may be used with other COTS equipment on circuits running in environments with high electrical interference.
Compact construction in a 19" 1U chassis with direct telecom connectors (RJ21) to host equipment and MDF.

Approval Reference
(Provisional) PA05/06527

  • Enables host equipment to operate within Network Rail's NR/L2/TEL/30003
  • Can be used on: FXS, FXO, 2 or 4 wire E & M
  • Low insertion loss
  • Low ring attenuation
  • No configuration required
  • No power required
  • Compact 19" x 1U mounting
  • Low MTTR
Not available

Basic Hardware

  • 24 x channels
  • Impedance nominal 600Z
  • Connector equipment RJ21 (50 way)
  • 19” mounting

Electrical Rating

  • Impedance nominal 600Z
  • Line current 50mA
  • Ring voltage 70 VRMS @ 25Hz
  • Insulation 2KV RMS
  • Insulation resistance > 20MΩ


  • Not suitable for xDSL circuits
  • Not suitable for circuits carrying SPM pulses
  • Not suitable for ISDN circuits
  • Lightning protection should be fitted externally (MDF)

Order Codes

  • MOD22014-12
  • MOD22014-24


  • Filter longitudinal >15dB @ 50 Hz, 20dB/decade roll-off
  • Insertion loss speech band < 0.6dB
  • Loop resistance <60Ω
  • Longitudinal conversion loss (LCL) >70dB 200 to 4000Hz
  • Crosstalk inter channel >80dB
  • Return loss >12dB @600Z


  • Temperature range -20 to +65 C
  • Rugged enclosure IP51
  • Humidity 95% non-condensing


  • Desktop, or rack mounting
  • W x H x D: 444 x 45 x 330 mm; Weight: 9.5 kg


  • Passive

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