ADMINISTRATION OPTIONS AND REQUIREMENTS — SYSTEM 85
7-35
Field 15 V4 Only
Used for non-ISDN trunk groups that interwork to ISDN trunk groups. Therefore,
field 15 only applies to non-ISDN trunk groups. Generally, trunk groups can use
both analog and ISDN-PRI (digital) transmission facilities. Any restrictions and
compatibility requirements are conveyed as information known as the BC code.
This field is used to populate the BC IE. Field encodes and their descriptions are:
0
1
2
3
4
Voice and Voice-grade data
Mode 1 data (56K-bps)
Mode 2 data (subrate up to 19.2K-bps)
Mode 3 data (also called packet mode)
Mode 0 data (64K-bps digital data)
Procedure 116 Word 1: DS1/DMI/ISDN-PRI Trunk Assignments
Each analog trunk circuit pack provides four circuits that are administered by using procedure 150.
Conversely, each DS1 provides 24 circuits (channels) that are administered by using procedure 116.
Figure 7-15, Procedure 116 Word 1: DSI Trunk Assignments to Equipment/Circuit Location (System
85 R2V4), depicts procedure 116, word 1. Each DS1/MFAT carrier will support a maximum of two
DS1s, each occupying one slot and located in slots 5 and 18. When a DS1/DMI/ISDN interface
(trunk applications) is located in slot 5, it functionally uses the six slots 0, 1, 2, 5, 6, and 7. When
the interface is located in slot 18, it functionally uses the six slots 13, 14, 15, 18, 19, and 20.