Set the conformance level and encoding for C1 controls in terminal replies.
If 'level' < 61 or high than the configured maximum this sequences does nothing.
level - 60 is the VT-xxx conformance level to activate (i.e.
level = 64 -> VT-4xx conformance).
level > 61, the parameter
7bit is used to set the encoding for C1 controls. If
7bit = 1 then encoding is use 7-bit controls. If
7bit is 0 or 2 then encoding is use 8-bit controls. If
7bit is explicitly set to any other value the encoding is not changed.