Business Telephone Systems

Carrier Services - T1 Lines

T1 Support

IP Office T1 trunks support both DNIS and ANI services, where available from the central office. Dialed Number Identification String (DNIS) Provides a string of digits to the IP Office depending on the number dialed by the incoming caller. This string can then be used to route callers to individual extensions, groups or services.

Automatic Number Identification (ANI) Provides IP office with a number identifying who the caller is. This may then be used for routing or computer telephony applications.

T1 trunk cards incorporate an integral CSU/DSU, eliminating the need for an external unit. The CSU function allows the trunk to be put in loop-back mode for testing purposes. This can be set manually, using the monitor application, or automatically from a Central Office sending a Line Loop Back (LLB) pattern. The DSU function allows the T1 trunk to be shared between data and voice services.

Analog Trunks (Loop Start/ Ground Start)

Loop Start

Loop start trunks are available on the IP office as plug in cards for the base unit or as a stackable 16-port module. The first two trunks on the stackable module are automatically switched to power fail sockets in the event of power being interrupted. They conform to the TIA/EIA-646-B standard.

The loop start trunks also support incoming caller line identification (ICLID) conforming to GR-188- CORE and GR-31-CORE standards. IP Office can use this information to route calls or provide it to computer applications to display additional information about the caller.

Ground Start

Ground Start trunks are available as a stackable 16-port module. See Section 2 for detail. The first two trunks on the module are automatically switched to power fail socket in the event of power being interrupted. They conform to ANSI T1.401 and TIA/EIA-646-B standards.

ISDN Basic Rate - IP400 Quad BRI

ISDN Basic rate provides 2 x 64K speech channels using Q.931 signaling and CRC error checking. Both point to point and point to multipoint operation is supported. Multipoint lines allow multiple devices to share the same line, however point-to-point is the preferred mode.

The following supplementary services are supported:

Least Cost Routing (LCR)

By configuring a Least Cost Route calls may be routed via an alternative carrier. Time profiles can also be used to allow customers to take advantage of cheaper rates at specific times. Multiple carriers are also supported. For example, if local calls and international calls are to go through one carrier between specific hours, all calls to a specific country through an alternative carrier and all other calls via a third carrier. Carrier selection using 2 stage call set up via in-band DTMF is possible.

Alternate Call Routing (ACR)

Alternate Call Routing allows calls to be placed via an alternative route should the primary route fail or be unavailable through congestion etc. ACR is compatible with LCR and VoIP and can be configured to "take" data channels for voice calls whilst preserving the data call, albeit with reduced bandwidth.

Network Numbering Schemes

IP Office employs fully flexible network numbering options. Dialed digits can be manipulated seamlessly to add and delete digits, access codes etc in order to fit into any numbering scheme. Two types of numbering schemes are commonly deployed - ‘Linked Numbering’ and ‘Node Numbering’ schemes. In linked numbering schemes each site within the network has a unique range of extension numbers and users simply dial the extension number of the called party. Often linked numbering schemes are used in very small networks (< 5 sites) with less than 500 extensions.

With node numbering schemes each site is given a node ID and the user when dialing extensions at other sites prefixes this. In this way extension numbers can be replicated across sites whilst still appearing unique across the network. Node numbering schemes are common in larger networks. Linked numbering schemes and node numbering schemes are sometimes both employed within the same network with node numbering employed at the large offices and linked numbering employed at clusters of satellite office