I have a Modicon NOM0200 unit connected to an access switch to send commands to various rs-232 devices. The Access switch requires a "disconnect string" to end communication with a particular port. The disconnect string is "CRTL+D", how can I send a "CRTL" keystroke from the NOM0200 unit? I know for carriage return it is "$R" is their a similar combination I can enter for "CTRL"?