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• CCITT Rec. K.12 (11/1988) – CHARACTERISTICS OF GAS DISCHARGE TUBES FOR THE PROTECTION OF TELECOMMUNICATIONS INSTALLATIONS
• Introduction
• 1 Scope
• 2 Definitions
• 3 Environmental conditions
• 4 Electrical characteristics
  • 4.1 Spark-over voltages (see §§ 5.1, 5.2 and Figures 1/K.12, 2/K.12 and 3/K.12)
  • 4.2 Holdover voltages (see § 5.5 and Figures 4/K.12 and 5/K.12)
  • 4.3 Insulation resistance (see § 5.3)
  • 4.4 Capacitance
  • 4.5 Impulse transverse voltage - 3-electrode tubes (see § 5.9 and Figure 6/K.12)
  • 4.6 Life tests (§§ 5.6, 5.7 and 5.8)
• 5 Test methods
  • 5.1 D.c. spark-over voltage (see § 4.1 and Figures 1/K.12 and 2/K.12)
  • 5.2 Impulse spark-over voltage (§ 4.1 and Figures 1/K.12 and 3/K.12)
  • 5.3 Insulation resistance (§ 4.3)
  • 5.4 Capacitance (§ 4.4)
  • 5.5 Holdover test (§ 4.2)
  • 5.6 Impulse life - all types of gas discharge tube (§ 4.6)
  • 5.7 Impulse life - additional tests for tubes designated EXT (§ 4.6)
  • 5.8 A.c. life – all types of tube (§ 4.6)
  • 5.9 Impulse transverse voltage (§ 4.5 and Figure 6/K.12)
• 6 Radiation
• 7 Environmental tests
  • 7.1 Robustness of terminations
  • 7.2 Solderability
  • 7.3 Resistance to soldering heat
  • 7.4 Vibration
  • 7.5 Damp heat cyclic
  • 7.6 Sealing
  • 7.7 Low temperature
• 8 Identification
  • 8.1 Marking
  • 8.2 Documentation
• 9 Ordering information
• APPENDIX I (to Recommendation K.12) – Definitions of terms associated with gas discharge tubes
  • I.1 arc current
  • I.2 arc voltage
  • I.3 breakdown
  • I.4 current turnoff time
  • I.5 destruction characteristic
  • I.6 discharge current
  • I.7 discharge current, alternating
  • I.8 discharge current, impulse
  • I.9 discharge voltage
  • I.10 discharge voltage/current characteristic
  • I.11 follow current
  • I.12 gas discharge tube
  • I.13 glow current
  • I.14 glow-to-arc transition current
  • I.15 glow voltage
  • I.16 holdover voltage
  • I.17 impulse spark-over voltage/time curve
  • I.18 impulse waveform
  • I.19 nominal alternating discharge current
  • I.20 nominal d.c. spark-over voltage
  • I.21 nominal impulse discharge current
  • I.22 residual voltage
  • I.23 spark-over
  • I.24 spark-over voltage
  • I.25 spark-over voltage, a.c.
  • I.26 spark-over voltage, d.c.
  • I.27 spark-over voltage, impulse
  • I.28 transverse voltage