AT&T Telephone DS1/DMi/ISDN-PRI Manual de usuario descargar pdf (Pagina 71)

NETWORK CONNECTIONS AND CONFIGURATIONS

2-15

Network Specific Facility

For outgoing calls from the customer-premises side, the 4E11 and 4E12 will accept a network specific

facility (NSF) but do not require that one be present.

For call-by-call trunk groups, the 4ESS will check for a NSF and will reject the call if one is not

present.

Synchronization

A 4ESS is always synchronized to the AT&T reference frequency. Therefore, for special-access

applications, the System 85 or Generic 2 normally uses a 4ESS as the master-clock source. A

particular ISDN-PRI facility may or may not be selected as the clock reference to the switch,

depending on the use and reliability of other interfaces. The rules and considerations for selecting a

synchronization source are detailed in chapter 5, Synchronization of Digital Facilities.

System 85 R2V4, Generic 1, or Generic 2 to a DACS

The DACS does not provide a DMI-MOS or ISDN-PRI and does not support those types of

connections. However, D4, ESF, and RBS are supported.

System 85 or Generic 2 ISDN-PRI to a 5ESS

A 5ESS is most frequently used by a LEC. It provides digital CO services, both to subscribers and

customer premises switches. For ISDN applications, a 5ESS must be equipped with 5e4.2 or later

software.

A System 85 or Generic 2 ISDN-PRI connects to the extended digital subscriber line (EDSL) circuit

pack in a 5ESS (only those configured with 5e4.2 Generic implement the network).

A 5ESS may or may not be synchronized to the AT&T reference frequency. A 5ESS has a lower

stratum clock (higher accuracy) than a System 85 or Generic 2. Therefore, this issue should be

verified for each specific configuration.

1 2 ... 66 67 68 69 70 71 72 73 74 75 76 ... 395 396

AT&T Telephone DS1/DMi/ISDN-PRI Manual de usuario Pagina 71