It's often necessary to connect to IOx from the IOS command line. This is typically done using telnet, for instance:

telnet 192.168.2.1 2070

Will access the IOx console, which provides details about IOx booting and therefore is a useful diagnostic tool. At this point you can either "exit" the shell in IOx to return to IOS or disconnect. To disconnect, it's necessary to "interrupt" the session. This is done using the interrupt character, which is Control-^ (control and caret or Control-Shift-6), then disconnecting:

IR809-DHCP#telnet 192.168.2.1 2070
Trying 192.168.2.1, 2070 ... Open

Poky (Yocto Project Reference Distro) 1.8 IR809-DHCP-GOS-1 /dev/ttyS0

IR809-DHCP-GOS-1 login:  <---------- Control-Shift-6 - then enter 'x'
IR809-DHCP#disc.         <----------- enter "disc" and return
Closing connection to 192.168.2.1 [confirm]                    <----------- return
IR809-DHCP#

Note: failing to disconnect will result in the telnet session remaining active. If you attempt to connect using telnet again you will get this error:

IR809-DHCP#telnet 192.168.2.1 2070
Trying 192.168.2.1, 2070 ...
% Connection refused by remote host

Just disconnect as shown above.