local tCableState = {}  -- Holds the state of all bundled cables on the computer.
 
-- Get the current state for all 6 sides.
for _, v in pairs( rs.getSides() ) do
  tCableState[ v ] = rs.getBundledInput( v )
end
 
-- If a bundled cable changes its state, then this function returns the event 'bundled_cable' and a table.
-- The returned table contains only sides that have changed and it has this format: { side = { new_value, old_value } }
function pullEvent()
  local bStatesChanged = false
  local tChangedCables = {}
  local event, p1, p2, p3, p4, p5 = os.pullEvent()
 
  if event == "redstone" then
    -- Iterate over all 6 sides of the computer.
    for _, v in pairs( rs.getSides() ) do
          local nBCInput = rs.getBundledInput( v )  -- Get cable input for current side.
          if  nBCInput ~= tCableState[ v ] then  -- Has the state changed?
            tChangedCables[ v ] = { nBCInput, tCableState[ v ] }  -- Add the changed side + its new and old values to the return table.
            tCableState[ v ] = nBCInput  -- Update the local state table.
            bStatesChanged = true
          end
    end
  end
 
  -- Turn the 'redstone' event into a 'bundled_cable' event if the state of a bundled cable has changed.
  if bStatesChanged then
    event = "bundled_cable"
    p1 = tChangedCables
  end
 
  return event, p1, p2, p3, p4, p5
end

-- Load API
if not os.loadAPI( "bc" ) then
  error( "Bundled-Cable Event API could not be loaded. :unsure:/>/>" )
end
 
while true do
  local sEvent, p1, p2, p3, p4, p5 = bc.pullEvent()  -- Here we call our customized event listener bc.pullEvent(), instead of os.pullEvent()
 
  if sEvent == "bundled_cable" then
        -- p1 will contain a table with all the sides that have changed, mapped to their new and old values, i.e. p1 := { "side" = { new_value, old_value } }
        local new = 1
        local old = 2
        for side, tValue in pairs( p1 ) do
          print( """..side.."" has changed from "..tValue[ old ].." to "..tValue[ new ] )
        end
  end
 
  if sEvent == "char" and string.lower( p1 ) == "q" then break end
end