User`s guide

System Administrator’s Guide – Release 7.2.3.x

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Revised: September 1, 2010

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interfaces support both circuit switched voice calls and TCP/IP data. The data connection can be used for

connectivity to another remote site on a dedicated T1 line or for connectivity to a service provider for Internet

access.

PRI Support

The Allworx server supports Primary Rate ISDN using the National Standard ISDN format (NI-2), Lucent

Custom 4ESS, Lucent Custom 5ESS, and Nortel DMS-100 switch types. The Allworx server ISDN interface is

always configured as the user side equipment with the intention of hooking to the service provider’s Central

Office (CO) network side equipment. The Allworx server interfaces have a fully integrated CSU/DSU and are

typically intended for direct short haul connection to the service provider’s smart jack. Consult the product

installation instructions for further information.

Note: When PRI operation is desired it is important to define exactly one PRI D channel for the Digital Line

and a minimum of one PRI B channel. The configuration must match the provisioning defined by the

Central Office with a typical configuration having 23 B channels on slots 1 through 23 and one D

channel on slot 24.

NFAS Support

Non-Facility Associated Signaling (NFAS) is a PRI where multiple T1 lines share the same D channel. The

Allworx server supports NFAS using the National Standard ISDN, Lucent Custom 4ESS, Lucent Custom

5ESS, Nortel DMS-100 switch types.

Note: The configuration must match the provisioning defined by the Central Office. A typical configuration

has 23 B channels on slots 1 through 23 and one D channel on slot 24 of the primary T1 line, plus 24

B channels on slots 1 through 24 of the secondary T1 line. To configure NFAS on the Allworx system,

the NFAS line with the D channel must be connected to the T1-A port.

Robbed Bit Signaling (RBS) Support

The Allworx server supports classical T1 Robbed Bit Signaling (RBS) trunk lines on a time slot by time slot

basis. Sometimes this functionality is referred to as T1 Channel Associated Signaling (CAS). The following

modes are supported:

• FXO Loop-Start

• FXO Ground-Start

• E&M Wink Start

• E&M Feature Group B

• E&M Immediate Start

For the above selections, operational use is basically the same as the corresponding analog interface types.

The precise signaling protocols for each interface are implemented in conformance with the procedures

documented in EIA/TIA-464C. Inbound Caller-ID is supported on the FXO modes, if the CO supports it and

the check box is enabled on the Outside Lines / Digital Lines / Modify page.

For primary CO line connectivity, the FXO Ground-Start slot choice is typically preferred to minimize the

possibility for glare conditions, especially when call volume is high. Furthermore, it is not guaranteed that the

network provides an explicit disconnect signal in FXO Loop-Start mode. Normally, the user would terminate a

call by hanging up the phone. However, if a call is under the supervision of the auto-attendant, the lack of a

terminating signal can cause a call to remain live for an extended period of time (tens of seconds) after the