Bell System Practices TOUCH-A-MATIC 2872A1M Identification, Installation, Connections, Operation, And Maintenance page 56

SECTION 503-603-101
$ TABLE N (Contd) 4
TROUBLE ANALYSIS - 2872AIM OR 2872A2M
,,,
TROUBLE
NUMBER FAILURE ADDITIONAL SYMPTOM POSSIBLE CAUSE REMEDIAL ACTION
24 Hum or Noise Unbalanced Check for unintentional
caused by electrical telephone line connections that might
apparatus (light cause an unbalanced
dimmer switch, etc) telephone line
Page 56
56 Pages