Have lines crossed!?

Question

I couldn't understand the meaning of have lines crossed in the sentence below:"We must have had our lines crossed, thank you for checking."I'd appreciate it if you help me in this order.Thanks

Answer 1

This colloquialism is in reference to the days of switchboards which were used for telephone communications. If the lines were crossed the person calling would not be connected to the intended receiver of the call. Therefore, if wires get crossed it indicates there is a miscommunication between the parties.