If you are missing your line cord or just want to replace your old one on your woodwall telephone this will do the trick.  This cord is 6-1/2' long.  Brown.

I was also told that:
The major/only difference between your telephone cords & speaker cords is that one end of the cord has "Phone (Earphone) Tips" on the wire ends instead of "Spade" lugs. Many 1920's, 30's, etc. radios have speaker terminal connectors which will accept spade lugs. Also many radios have "1/4 inch Earphone/Speaker" jacks. If you use a standard "phone tip" to "1/4 inch phone" adapter, the spade lugs will fit under the screws. Therefore, your telephone cords will work for most old radio speakers.