The portions of the operator's talking circuit that are located permanently in the switchboard cabinet are in such cases terminated in a jack, called an operator's cut-in jack. - Cyclopedia of Telephony & Telegraphy Vol. 1 A General Reference Work on Telephony, etc. etc.
Bellinger recommends choosing one topic to focus on -- "the expression 'jack of all trades, master of none' holds true especially in the Web 2.0 world" -- and working on engaging with the top people in that area rather than trying to tackle all the world's problems at once. - Lauren Zumbach: The New Twitter Revolution
"You cannot become an expert if one day you work in maternity, the other day you work in the long-term care, and then you are in emergency room," she said, referencing the phrase "jack of all trades, master of none." - The Full Feed from HuffingtonPost.com
And so she proved, in small things at first, as translator, courier, embassy bricoleur - what you call jack-of-all-trades - and later as secret agent in the field ... and you know what that means. - Watershed
You would think that since the jack is the same the requirements are the same. - Apple question « BuzzMachine