“Ten-four, copy that, I'm on my way for the drop-off.”？

[on the way]

This is an expression I came across in an episode of a TV series when Miranda is calling a sectary in false identity.Two of the words in this sentence are particulaly tricky for me.One is 10-4 and the other is drop-off.Any help in enlightening me on the understanding of these two expressions will be much appreciated.

 

[BobK]

Radio/police jargon:

10.4 - OK [which originally, now I think of it, entered the language as a piece of radio-operators' jargon]
copy that - message received

The drop-off is a term often used in crime dramas: the time and place (or the event as a whole) when something (e.g. ransom money) is dropped off.

b

PS What happens next is the 'pick-up'.

 

[on the way]

Radio/police jargon:

10.4 - OK [which originally, now I think of it, entered the language as a piece of radio-operators' jargon]
copy that - message received

The drop-off is a term often used in crime dramas: the time and place (or the event as a whole) when something (e.g. ransom money) is dropped off.

b

PS What happens next is the 'pick-up'.

Thank you very very much,Dear Bobk,if I may.You answered many many of my questions.My gratitude is beyond words really.Thank you again.Best wishes to you!:-D