Word difference question - reply (返事 vs 返信)


A simple questions here on word usage.

For reply I have always used 返事. Today however a friend mailed me and said 返信.
This word is new to me. How does it differ?




Both mean reply, but 返信 can only be used if the reply is transmitted via code
(be it letter, e-mail, flag semaphore, Morse code etc. as opposed to speech
(including telephone), gesture etc.). Note that 返信 does not refer to the
object that contains the reply; it refers to the reply.

[code]

    Eメールで返事しといた　->　OK
    Eメールで返信しといた　->　OK
    大声で返事した　->　OK
    大声で返信した　->　Weird, speech isn't via code
    
[/code]

**EDIT** :  
Re: `transmitted via code`, I think the best practical way of defining it
would be "not via speech or gesture". To your example, spy talking in code
would be 返事 because the transport layer (haha you can tell I'm an Engineer) is
still speech, but I think it's border line. If they'd do the same on the
phone, that will be still 返事. However, if they transmit encrypted message via
phone (like by reading out bunch of numbers etc.) or even in person, that
would be now 返信 because it's no longer via speech.




Both mean reply, but 返信 can only be used if the reply is transmitted via code
(be it letter, e-mail, flag semaphore, Morse code etc. as opposed to speech
(including telephone), gesture etc.). Note that 返信 does not refer to the
object that contains the reply; it refers to the reply.

[code]

    Eメールで返事しといた　->　OK
    Eメールで返信しといた　->　OK
    大声で返事した　->　OK
    大声で返信した　->　Weird, speech isn't via code
    
[/code]

**EDIT** :  
Re: `transmitted via code`, I think the best practical way of defining it
would be "not via speech or gesture". To your example, spy talking in code
would be 返事 because the transport layer (haha you can tell I'm an Engineer) is
still speech, but I think it's border line. If they'd do the same on the
phone, that will be still 返事. However, if they transmit encrypted message via
phone (like by reading out bunch of numbers etc.) or even in person, that
would be now 返信 because it's no longer via speech.

