picket fencing

Picket fencing is slang for the chopping effect sometimes heard by cell phone users at the edge of a cell's coverage area, or (more likely) by the landline user to whom the cellphone is connected. "Picket fencing" refers to the way portions of speech are stripped from the conversation, as if the listener was walking by a picket fence, and hearing a conversation on the other side that changes audibily depending on the position of the pickets relative to the listener.
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