Trunk Interface
Field
0 or 1 in each bit
0000 1011
If the trunk interface is E1, bits five, seven, and eight of the time slot-16 word in frame zero (the frame containing the multiframe alignment signal) can be used by a telephone company for country-specific requirements. Set these bits to 0 or 1 in accordance with any telephone company requirements. Bits one through four and bit six are fixed at 0. The bit order is one, two,... eight.