I've been asked to replace the curly telephone cord that connects between the handset and main unit (Uniden SSE27) … wiggling the cord causes static and the phone often disconnects when being used, so probably a broken wire or faulty plug.
The plug is quite slim compared to other phone cables, so probably RJ11-4C/4P-US modular plug type?
Not a lot of retailers left selling these, but some I've found describe the cable as "cross-over" … is this normal for wired phones?