Note: The intercharacter interval may be of any duration. The signal sense of the intercharacter interval is always the same as the sense of the stop element, i.e. , "1" or "mark[?]."
Source: from Federal Standard 1037C and from MIL-STD-188
... is done by controlling the switch points; this can be done:
by other personnel than the driver, often remotely from a traffic control[?] point
by the driver from his ...
Kids.Net.Au - kids safe portal for children, parents, schools and