Hello Rupesh,
I think you can increase the time in "exec-timeout" at the line as follows.
Exsample;
Router(config)#line con 0
Router(config-line)#exec-timeout 60....minute
Router#sh line con 0 | b Timeouts:
Timeouts: Idle EXEC Idle Session Modem Answer Session Dispatch
01:00:00 never none not set
<...snip...>
Incidentally, if you don't specify the time, it'll be 10min by the default.
HTH
Tomoyuki