Both expressions mean that the message, written or spoken, has been received and understood.

Roger that is used for aviation and military communications.

Copy that is used for military, amateur and CB radio communications.

Roger was developed and used in the early days of radio when it was discovered some words and letters transmitted less well than others. so a universal/international way of individually spelling out a word was developed. This is has below.

A = Alfa = deliberately misspelt of Alpha

B = Brave

C = Charlie

D = Delta

E= Echo

F =Foxtrot

G = Golf

H = Hotel

I = Indigo

J = Juliett deliberate misspelling of the Girls name

K = Kilo

L = Lima

M = Mike

N = November

0 = Oscar

P = Papa

Q = Quebec

R = Romeo

S = Sierra

T = Tango

U = Uniform

V = Victor

W = Whiskey

X = X-ray

Y = Yankee

Z= Zulu International adaption.

you must say the words has written to get your clear message across.

I have been an Alfa one, A bravo, a Delta and A Charlie call sign.

over and out from

Juliett Oscar Hotel November