AOff
AOff Switch off power to SCC and -5 volt supply if portB not in use The AOff procedure always switches off power to the SCC and the -5 volt supply if serial port B is not in use. If the internal modem is installed,
connected to port A, and switched on, this procedure switches off power to the
modem. If any of these conditions are not met, it switches off power to the serial
driver chips, unless they are being used by port B.