The OED suggests it was coined in the 1960s by an employee at Bell Labs, Don Macpherson, citing an article in Telecom Heritage magazine (1996 No. 28) “His thought process was as follows: There are eight points on the symbol so octo should be part of the name. We need a few more letters or another syllable to make a noun... (Don Macpherson… was active in a group that was trying to get Jim Thorpe's Olympic medals returned from Sweden). The phrase thorpe would be unique.”

https://en.wikipedia.org/wiki/Jim_Thorpe