Possible Clues:

• Even when it's wired correctly, it can still shock
• Message that includes note on sheep
• Message sent by European member cutting one form of public transport
• Message left in note, eg 'Castle in the morning'
• Changing gear, melt wire
• The phone call replaced it
• Email's ancestor
• Message sent by wire and delivered in written form
• How tidings could arrive spread restriction from the east
• Uplifting spread allowed such a communication