AT&T DS1/DMi/ISDN-PRI manual Generic, 24INTRODUCTION

1-24INTRODUCTION

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 Voice only — used for voice application extensions (such as DCP and ISDN-BRI extensions, analog lines, and analog trunks)

1 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

2 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.

3 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)

4 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)

5 Voice-grade data — used for data applications that use modems

6 Mode-0 data — used for facilities that transmit 64K-bps data (DCP and BRI extensions, DMI- BOS trunks, and ISDN-PRI facilities).

7 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.

8 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.