Introduction to switch integration

Switch integration is a means of data communication between the host switch and the Avaya S3400 Message Server. Data communication includes all call-related information such as the called party, the calling party, and whether it is a direct call or a transfer call. This data that is passed between the switch and the messaging server governs how the Telephony User Interface Call Manager handles the call.

Switch integration falls into various categories, which a particular switch may or may not support. Factors that affect the choice of integration include:

• Switch type
• Bearer channel type
• Signaling protocol type

The bearer channel is the channel that carries voice traffic, whereas the signaling protocol is the protocol used for signal transfer.

Types of switch integration

The Avaya S3400 Message Server supports the following types of switch integration:

• Controlled Lan (C-LAN)
• Q-Signaling (QSIG)
• Digital Set Emulation (DSE)
• Serial RS232
• In-Band
• Digital Multiplexed Interface - 4 (DMI-4)

Different switches require different methods of switch integration. The following sections describe each of these switch integration methods and the signaling protocols that each uses.

Controlled Lan (C-LAN)

In Controlled-LAN (C-LAN ) switch integration, a controlled LAN passes proprietary messages between the switch and the messaging server. A C-LAN circuit pack on the host switch provides C-LAN integration. The C-LAN circuit pack provides an Avaya proprietary protocol over TCP/IP, for integrating the host switch with the messaging server. This Avaya proprietary protocol is an out-of-band protocol, which makes use of analog lines to provide the voice path. The C-LAN circuit pack provides IP access to the host switch. C-LAN prepares the signaling information for TCP/IP transmission over an Ethernet LAN. C-LAN switch integration supports Tip/Ring port types.

The C-LAN circuit pack (TN799) provides the data link interface between the switch processor and the transmission facilities. In the context of the Avaya S3400 Message Server, the C-LAN circuit pack provides an Ethernet interface to allow TCP/IP connectivity from the host switch to the server.

The following figure illustrates the integration between the host switch and the S3400 Message Server, using a controlled LAN.

Key to the illustration

Figure 1: C-LAN Integration

C-LAN supports two functions:

• Message Waiting Indicator (MWI) 'on' or 'off' control: This function notifies the subscriber of new messages, via the switch MWI. When the subscriber retrieves the message, the indicator goes off.
• Call information: Calling party ID, called party ID, internal call or external call, and direct call or redirected call.

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Q-Signaling (QSIG)

Q-Signaling (QSIG) enables switches that are made by different vendors to communicate with each other. This standards-based, private networking protocol is based on Q.931 standards (ISDN) and is an internationally standardized method of networking communication systems.

With QSIG integration, a digital pathway between the host PBX and Avaya S3400 Message Server transmits both call information and voice communications. An ISDN digital link provides the pathway. This digital link provides 24 channels that connect to the Dialogic T1 card or 30 channels that connect to the Dialogic E1 card. The Dialogic card in turn, connects directly to the PBX using a QSIG link. Such a setup makes the S3400 Message Server appear as another PBX in the network. Within the D-Channel, the destination PBX receives the routing information such as the source of the call and the reason for its arrival. The S3400 Message Server receives call information from the supplementary code in the D-Channel, which routes call reasons directly to the mailboxes. The MWI server uses the supplementary code service to set and cancel the message waiting indication.

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Digital Set Emulation (DSE)

DSE integration uses a digital port board that emulates eight digital telephone sets with displays. In addition to terminating eight digital lines from the switch, the DSE board interprets the display information for those lines and passes it to the messaging system as control information.

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Serial RS232

Switches such as central office switches and other large switches use serial RS232 data links for control messages. The Avaya S3400 Message Server supports one RS232 link per Messaging Application Server (MAS). Serial RS232 integration supports Tip/Ring port boards.

The types of serial RS232 integration are:

• Simplified Message Desk Interface (SMDI) or Simplified Message Service Interface (SMSI): Switches using this interface include Lucent 5ESS and Nortel DMS100/SL-100.
• Proprietary serial integration: A proprietary serial interface, which is switch-dependent and includes NEC 2000 IVS and 2400, and Intecom IBX.

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In-Band

Many switches do not use a separate data link to communicate control information with the messaging system. For these switches, control information is sent within the voice channel. These integration types are known as in-band or mode-code. The Avaya S3400 Message Server supports in-band integration with tunable parameters such as customized in or out digit strings, timing, and delimiters.

In-band integrations are used primarily for small systems. Some switches, for example Alcatel, send call progress indicators in-band using Dual Tone Multifrequency (DTMF) tones. The PBX sends DTMF tone strings to the MAS’s port, when the call is first placed to the port. The MAS is configured to recognize the format of these tone strings and to interpret the information accordingly.

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Digital Multiplexed Interface - 4 (DMI-4)

The Avaya S3400 Message Server supports Mitel SX-2000 and Mitel SX-2000 Light switches with Digital Multiplexed Interface - 4 (DMI-4) integration or Simplified Message Desk Interface (SMDI) integration. In a DMI-4 integration, the PBXLink DMI-4 emulates Mitel Superset 430 digital display telephones. The DMI-4 converts information from the digital telephones to its analog ports, which correspond with the Avaya S3400 Message Server voice ports. The PBXLink creates and passes a standard SMDI packet containing the call information provided by the PBX, to the MM (Modular Messaging) server, which then answers with the proper greeting.

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