8 7 6 5 4 3 2 1 1 H G F E D C B A A Type 0 request 1 response If bit A equals to 0 (request): bits H-B Spare If bit A equals to 1 (response): bits C B Response indicator 0 0 insufficient information (note) 0 1 no loop exists 1 0 simultaneous transfer 1 1 spare bits H-D Spare NOTE - The value "insufficient information" may be received due to interworking.