Sorunuzun bir sitede rastladığım yanıtı:
In 1859, Western Union standardized on the "92 code" in which the numbers from 1 to 92 were assigned meanings. It was in this list that 73 got its present meaning. Later more numbers were added. Here's a partial list:
1  Wait a moment  
2  Important Business  
3  What time is it?  
4  Where shall I go ahead?  
5  Have you business for me?  
6  I am ready  
7  Are you ready?  
8  Close your key; circuit is busy  
9  Close your key for priority business (Wire chief, dispatcher, etc)
10  Keep this circuit closed  
12  Do you understand?  
13  I understand  
14  What is the weather?  
15  For you and other to copy  
17  Lightning here  
18  What is the trouble?  
19  Form 19 train order  
21  Stop for a meal  
22  Wire test  
23  All copy  
24  Repeat this back  
25  Busy on another wire  
26  Put on ground wire  
27  Priority, very important  
28  Do you get my writing?  
29  Private, deliver in sealed envelope  
30  No more (end)  
31  Form 31 train order  
32  I understand that I am to ...  
33  Car report (Also, answer is paid for)  
34  Message for all officers  
35  You may use my signal to answer this  
37  Diversion (Also, inform all interested)  
39  Important, with priority on thru wire (Also, sleep-car report)  
44  Answer promptly by wire   73  Best regards  
88  Love and kisses  
91  Superintendent's signal  
92  Deliver promptly  
93  Vice President and General Manager's signals  
95  President's signal  
134  Who is at the key?  
Editor Note; Had an input for  99 = Get Lost (probably unofficial)
Kaynak: 
N2EY