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INTRODUCTION
Generic 1
For information about how BC is done for Generic 1, refer to the AT&T DEFINITY 75/85
Communications System Generic 1 and System 75 and System 75 XE Feature Description (555-200-
201).
Generic 2
Generic 2 continues the bearer capability concept with bearer capability class of service, (BCCOS).
With BCCOS, switch administration software provides a range of codes from 0 through 255. Codes 0
through 8 are predefined as:
0
1
2
3
4
5
6
7
8
Voice only — used for voice application extensions (such as DCP and ISDN-BRI extensions,
analog lines, and analog trunks)
Mode 2 data — used for EIA data terminations, and DCP or BRI data modules that do not
operate as packet mode data and are optioned for any of the following data rates: low, 300, 1200,
2400, 4800, 9600, or 19.2K-bps
Mode 3/2 adaptive data — used for data applications that can run both mode 3 and mode 2 (such
as BRI, PC/PBX, and the 3270 data module). The connection is first established with mode 3; if
mode 3 fails, mode 2 is used.
Unknown digital — used for those calls of any mode (0-3) where the signaling message does not
specify a mode (such as DS1 trunks using common-channel or 24th-channel signaling)
Unknown analog — used for voice or voice-grade data calls where the signaling message does not
specify a type (such as analog trunks and robbed-bit DS1 trunks)
Voice-grade data — used for data applications that use modems
Mode-0 data — used for facilities that transmit 64K-bps data (DCP and BRI extensions, DMI-
BOS trunks, and ISDN-PRI facilities).
Mode 1 data — used for 56K-bps synchronous data applications. The appropriate data module
must be installed and optioned for 56K-bps operation.
NOTE: This arrangement can be used to support the special format required for ACCUNET
switched digital service or 56K-bps basic service. DCP uses a mode-2 handshake unless an
MPDM/M1* data module is used.
Mode 3 data — should be administered for those applications requiring packet mode data.
Lines, trunks, and AAR/ARS preferences are assigned the default BC when one is not administered.
Generic 2 BCCOS defaults are intended to make a Generic 2 switch operate like a System 85 R2V4
(that is, Generic 2 will insert modem pool members and block calls). Table 1-3, Bearer Capability
Class of Service, lists the default values for common switch parameters.