Hi, I had this problem on several ISR G2 routers using putty, MTPutty, and Tera Term. I solved it by typing esc+q+shift then ? Hope this saves someone an hour or two. Thanks.
Hi, On a 2800 series router, specifically tested on a 2851 running 15.1.4 M4, try 'telephony-service' in global config. ('file privilege 0' command was not valid, 'ip http path flash:' there was no change)