The Bt8110 requires an external lookup table ROM. The Bt8110B has an internal lookup table ROM, or can use an external lookup table ROM. When in direct framer interface mode, transparent channels in the Bt8110 will operate at 56 kbit/s; the Bt8110B operates at 64 kbit/s. A hardware control, direct framer interface mode has been added to the Bt8110B. For more details on the Bt8110B mode controls, refer to Table 1-1 and Table 1-4.