Your brother's computer appears to be signalling you in Morse code Mr. D. Perhaps U?
I'm no beep expert but FL310 once or twice posted the following:
1 = DRAM refresh not working
2 = Parity circuit not working or parity status bits are not
cleared when parity is disabled
3 = First 64k memory test failure
4 = System timer is not counting properly
5 = Processor register tag test failure
6 = 8042 keyboard controller Gate A20 error
7 = Processor exception error encountered
8 = Display memory R/W test error (non fatal)
9 = ROM BIOS checksum error
10 = CMOS shutdown register Read/WRITE error
Is that what you are referring to? I admire your technique. Where do you poke these damn machines in order to get them to behave?