BusinessPhone Communication Platform 4.0
Facilities

## ISDN S‑Interface

## Definition

A S-interface offers the possibility to connect ISDN terminals on the user side.

### Terms

ISDN |  | Integrated Services Digital Network

S |  | S-reference point, user side (= 2B+D user interface = S-interface)

T |  | T-reference point, network side (= 2B+D network interface or 30B+D network interface = T-interface)

TE |  | Terminal Equipment, e.g.: Telefax G4 PC with ISDN board PC with ISDN board and telephone Terminal adapter Videophone ISDN telephone Point of sales terminals

As regards ISDN-telephones, only basic functions concerning voice communication are supported. Therefore, we recommend to continue to use the proprietary digital system telephones (DIALOG 3000).

## Use

ISDN-terminals that are in compliance with the ACA (Australian Communication Authority), ETSI (European Telecommunications Standards Institute) recommendations (EURO-ISDN) and also country specific versions of the ETSI standard are supported on the S-interface:

- ISDN Telefax G4
- ISDN PC cards
- ISDN LAN cards
- ISDN Terminal adapter
- ISDN Videophones
- ISDN telephone
- ISDN Personal Conferencing Video Systems (e.g. Intel Proshare)
- ISDN X.25 terminals

The main purpose/application is to support data and video transmission in temporary “dial-up” connections using the public ISDN capabilities.

It is NOT intended for in-house PC networks. For this purpose, a PC-LAN meets the requirements (data rates far higher than 64kbps as provided on an ISDN-B channel) much better than an ISDN-connection via a PBX.

## Operation

#### Two types of bus configurations for different requirements are possible for the S-interface

- point-to-multipoint – short passive bus
- point-to-multipoint – extended passive bus

Point-to-multipoint is a user access supporting more than one logical data link (usually one per ISDN terminal) by a single network termination.

The difference between a short passive bus and an extended passive bus is on the one hand the line length and on the other hand the location of the TEs on the bus.

Note

For more information, see Installation Instruction ASB 150 02 (1531-ASB 150 02 Uen).

#### The following bearer services are supported at the S-Interface

Definition of “bearer”:

- A bearer is a type of telecommunication service that provides the capability for the transmission of signals between two ISDN interfaces.

##### Circuit mode (64 kbps)

- Speech
- Unrestricted digital information
- Unrestricted digital information with tones/announcements (7 kHz)
- 3.1 kHz audio
- Video

##### Packet mode

- through the D-channel (9,6 kbs) *)

*) developed according to the specifications of the Austrian Market see Facility description National Specific Functions (363/155 34-ASB 150 02 Uen)

#### General information concerning the numbering plan of the S-interface

Each S-interface and each connected ISDN terminal supporting its own MSN (= Multiple Subscriber Number) require a directory number in the system.

These ISDN directory numbers will correspond to route access numbers, normally used for trunk routes.

The S-Interface can only have one common directory number assigned.

The TEs can have one or more MSN assigned (depends on the terminal).

##### Example:

4 route access numbers, corresponding to

- 1 S-interface => 1 common number
- 3 TE => 3 individual numbers = 3 MSN

The “individual number” = MSN for the second TE is e.g.: 4738

The S-interface and all connected TEs use the same trunks, e.g.: trunk numbers 700 and 701.

This means that the S-interface and all connected TEs are assigned to the corresponding route numbers in which these trunks (700 and 701) are included.

### Facility overview

#### The following features are supported at the S‑interface

##### Supplementary services (according to ETSI)

Which supplementary services are provided to the S‑interface depends on the subscription of supplementary services from the public network provider as well as on the programming of the T- and S- interfaces.

For more informations concerning each topic, see the relevant chapter in this document

- ISDN SS Advice Of Charge (AOC)

- permanent AOC-D (=Advice Of Charge, During the call)
- permanent AOC-E (=Advice Of Charge, at the End of the call)

- ISDN SS Calling Line Identification Presentation (CLIP)
- ISDN SS Calling Line Identification Restriction (CLIR)
- ISDN SS Connected Line Identification Presentation (COLP)
- ISDN SS Connected Line Identification Restriction (COLR)
- ISDN SS Malicous Call Identification (MCID)
- ISDN SS Multiple Subscriber Number (MSN)
- ISDN SS Subaddressing (SUB)

##### ASB 150 02 proprietary system features

- Abbreviated dialling – Common numbers

- This means that the number of an internal or external destination is stored in the memory and called by dialling the abbreviated number.

- Rerouting on busy

- Rerouting on busy means that, if an ISDN terminal cannot be reached (e.g. both trunks are busy on the interface), any alternative route destination(s) can be used as “diversion position”.

- CIL (=Call Information Logging)

- Stored data is:

- calling number (common number of the S‑interface or the MSN of the individual TE)
- called or connected number, connected number (if provided) overrides called number (this facility is only applicable for calls to a S‑interface)

- CM (=Call Metering)

- Information on call charges will be stored.

- LCR (=Least Cost Routing)

- Least Cost Routing selects the most economic carrier for an entered destination number.

- Music on hold

- TE waiting in park state will receive music or other recorded information either during transfer procedure only, or until speech connection is established.

- System time

- Date and time is provided to the TE. Supported info is: year, month, day, hour, minute.

## Capacity

- The capacity of TEs refers to the total capacity of extensions in ASB 150 02, consisting of analogue telephones, system telephones and ISDN terminals
  (see System Overview, 1555-ASB 150 02 Uen).
- A maximum of 255 route numbers may be configured in the system (including all individual and common numbers).
- Up to eight TEs links may be connected to the S‑interface, whereby each of them may use 2 logical links (circuit mode and packet mode).
- 8 (4) S-interfaces per BTU-B_ board, 4 S‑interfaces per MFU board
- Max. 24 S-interfaces per system.

## Limitations

The sum of analogue trunks, tie lines and number of B‑channels on digital trunks and S-interfaces is limited to 120 individuals.

Only 2 TEs per ISDN link can be powered via the ASB 150 02 (see Installation Instruction ASB 150 02, 1531-ASB 150 02 Uen).

Only incoming and outgoing calls can be handled by ISDN telephones. No Inquiry call or transfer can be done from these telephones.

Calling the S-interface, it is not possible to use the Call back function.

Calling the S-interface, it is not possible to use the Notify function on the OPERATOR console.

Intrusion is not accepted by the S-interface.

There is no possibility to use a S-interface as a Diversion- or Follow me- address.

If an incoming ISDN call with a bearer service higher then “speech” (i.e. “data”) has been accepted by the destination, no rerouting to a second destination is allowed.

## Programming

The following commands are only accessible via BMS/RASC:

Note

The selected type of connection (T‑interface or S-interface) has to correspond to DIP switching of the interface type on the BTU-B_/MFU board. If the DIP switching does not correspond to the selected type of interface, a warning will be generated. (see Installation Instruction ASB 150 02, 1531-ASB 150 02 Uen)

5401 |  | Create a route

This command is normally used to create a trunk route.

In case of the S-Interface, the command is used for defining the common directory numbers of the interfaces as well as the MSN numbers of the connected TEs.

3201 |  | Trunk route members

3304 |  | First alternative route

3306 |  | Second alternative route

The following commands have to be programmed, if “ISDN-link user interface (-S)” has been selected:

1951 |  | Interface type

Note

The commands 1910 and 1951 must always state the same valid data!

1952 |  | Signaling protocol

1953 |  | Type of bus

1954 |  | Charging information provided to the TE?

1955 |  | MCID activation request allowed from TEs ?

1956 |  | MSN provided to TEs ?

Note

This feature can only be used, if the ISDN-terminals are programmed also with the MSN!

1957 |  | Number restriction allowed from TEs ?

1958 |  | Common access number

1971 |  | Assigned TEI values

## Equipment

The BTU-B_/MFU can be used either for the T- or the S‑interface.

Regarding the DIP switches following configurations are possible on:

- BTU-B_:

- 0 T-interface, 8 S-interfaces
- 2 T-interfaces, 6 S-interfaces
- 4 T-interfaces, 4 S-interfaces
- 6 T-interfaces, 2 S-interfaces
- 8 T-interfaces, 0 S-interface.

- MFU:

- 0 T-interface, 4 S-interfaces
- 1 T-interfaces, 3 S-interfaces
- 2 T-interfaces, 2 S-interfaces
- 3 T-interfaces, 1 S-interfaces
- 4 T-interfaces, 0 S-interface.

Revision: H © Ericsson Enterprise 2003