BusinessPhone Communication Platform 4.0
Facilities

## Austria – Support Of Packet Mode Terminals

## Definition

This document should be seen as a supplementary document to the ISDN Facilities description (268/155 34-ASB 150 02 Uen) which focuses especially on the support of packet mode terminals (based on X.25/X.31), for the Austrian Market.

ASB 150 02 supports two different kind of transfer modes for the bearer services on the S-Interface:

- Circuit mode
- Packet mode

For the bearer service packet mode ASB 150 02 supports a maximum of 9,6 kbs through the D‑channel.

The behaviour of the circuit mode calls and packet mode calls are different in sense of switching and routing within ASB 150 02.

## Use

The support of packet mode connections on the S‑Interface is used for terminals (e.g. Point Of Sales Terminals; POS) which do not support the circuit mode data calls.

This functionality provides the possibility to save a dedicated Basic Access (BA) only for the POS traffic, which was done in the most cases more or less independent from the ASB 150 02 system.

## Operation

Packet mode terminals will be connected to the S‑Interface in the same way as all the other ISDN equipment such as ISDN telephones or PC-cards.

ASB 150 02 supports packet mode terminals which sends X.25 packets over an ISDN BA using the Service Access Point Identifier (SAPI)* value equal to 16 and a Terminal Endpoint Identifier (TEI)* value in the non-automatic range (0-63) (*: address mechanism in Layer 2).

Compared to the circuit mode calls which can be routed through the switch to more or less every directory number in the system, the routing of packet mode calls is defined by programming from one data link on one S-Interface to another data link on a T‑Interface, both located on the same BTU-B / MFU board (see picture below).

The contents of the X.25 packets are not examined by ASB 150 02, they are routed unchanged between the defined data links.

ISDN Terminal equipment (TE) supporting the bearer service circuit mode or packet mode can be mixed on the S-Interface and also be used independently, due to the different SAPI (circuit mode=0, packet mode=16).

Each packet mode terminal must be subscribed to the network operator, to get it‘s own assigned TEI value (for SAPI 16) and it‘s own national significant number which can be, but may not be the same as used for the circuit mode calls. Both assignments are hereby related to the BA, used for the packet mode traffic.

The assigned TEI from the network operator which has to be stored in ASB 150 02 at the T-Interface can be, but may not be the same as stored on the packet mode terminal due to fact that ASB 150 02 is able to perform a TEI conversion.

Most of the packet mode terminal suppliers are maintaining their products (e.g for software updates) by setting up a packet mode communication to the terminal, but there exists also products which will be maintained via a circuit mode call. In the latter case it is necessary that this terminals also have an internal directory number assigned in order to be reached.

### Read out statistics via RASC

RASC provides statistics about the packet mode communication link(s). The received information is available for each BTU-B/MFU card, which has assigned packet mode communication links.

View the statistics under:

- MAINTENANCE-> SYSTEM-> PMC supervision

Content of the statistics:

- connected interfaces, A- and B-side of a packet mode connections (If),
- used TEI values (TEI),
- state of data link (State),
- number of X.25 packets that are transmitted towards a link, A-/B-side, (Tx),
- number of X.25 packets that are discarded (Discard)

## Capacity

- A maximum of eight packet mode communication links can be used per S/T-interface.
- A maximum of eight TEs can be connected to the S‑Interface, whereby each of them may use 2 logical links (circuit mode and packet mode).
- A maximum of 32 packet mode communication links are possible to establish per BTU-B (4 T to S links) and 16 per MFU (2 T to S links) or a sub-equipped BTU-B.
- A maximum of 3 BTU-B / MFU boards can be programmed for the packet mode handling
- The maximum size of un-segmented X.25 packets is 260 octets.

Hinweis

There exists some POS terminal suppliers, which provide the functionality to connect only one POS terminal to the S-Interface and all further POS terminals are connected in a kind of internal bus configuration to the first POS terminal. This kind of solution has the advantage that only one X.25 terminal has to be subscribed to the network operator as well as only one packet mode communication link will be occupied in the system.

## Limitations

- A maximum of 2 TEs per S-interface can be powered via the BTU-B / MFU, the others need an own dedicated power supply
- Only TEI values in the non-automatic range (0-63) can be used.
- Routing can only be done between packet mode communication links on the same BTU-B / MFU board.

## Programming

The following commands are only accessible via BMS/RASC:

Hinweis

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 Instructions, 1531-ASB 150 02 Uen).

Hinweis

Following settings have to be performed if only packet mode terminals are connected to the S-Interface.

If there exists a mixed configuration between packet mode and circuit mode terminals please refer to the programming mentioned in the ISDN Facilities description (268/155 34-ASB 150 02 Uen).

1951 |  | Interface type

1952 |  | Signaling protocol

1953 |  | Type of bus

1980 |  | Packet Mode Communication (PMC) links

## Equipment

- At least FECU Index 1 for Release ASB 150 02 R11 or higher
- BTU-B/MFU

Revision: B © Ericsson Enterprise 2003