Transformer hum through phone line caught me off guard at a ranch install

Last Tuesday I was terminating a DSC panel at a 40-acre ranch outside Boise when the customer called the landline to test the dialer, and all we heard was a nasty 60-cycle buzz over the speaker. Turns out the old alarm transformer was mounted right next to the phone entry block, and the magnetic field was coupling straight into the pair. Anyone else run into this and had to relocate the transformer, or did you just shielded the cable and call it good?

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1 Comment

emma5221mo ago

Moved mine three feet away from the phone block and the buzz disappeared completely.