BusinessPhone Communication Platform 4.0
Facilities

## External Line Key

## Definition

External line key is one of the traffic functions that can be assigned to the programmable keys on any digital Telephone.

An optional trunk can be represented on each key.

The help of an external line key gives the extension user a feeling of having direct access to the trunk.

This function is especially useful when the system is entirely or partly to be used as a key system or as a private trunk line.

## Operation

### Incoming calls

A call is signalled by the trunk's lamp which starts to flash rapidly.

If the extension is free, the acoustic ring signal that has been programmed for the key will be received.

If the extension is busy with another call, a short, muted ring burst will be supplied. (Not applicable if the key has been programmed not to ring).

A call via an external line key is not shown on the display.

### Answer

The call is answered by the user as follows:

1. Press external line key whereupon lamp shows connecting control-flashing.

- Ring signal ceases and extension obtains speech connection with caller.

Is the system connected to an ISDN trunkline, you will also get the national significant number of the external calling party presented on the display. Further information see ISDN - Supplementary Service CLIP (268/155 34-ASB 150 02 Uen).

### Outgoing calls

A call is initiated as follows:

1. Press key in idle state, that is, when lamp is extinguished.

- Lamp shows connection control.
- Caller hears external dial tone and can then dial relevant external number.

#### Analogue trunk line

The display shows the dialled digits:

#### ISDN trunk line

The display shows the dialled external number and also the call status message in the same way as it is used for internal calls.

The following call status messages will be indicated:

- Free
- Busy
- Speech
- Unknown
- Incomplete
- Congestion

If the outgoing call is answered by another number than the dialled one, the national significant number (public destination code + public subscriber number) of the party actually connected will be presented on the display. Further information see ISDN - Supplementary Service CLIP (268/155 34-ASB 150 02 Uen).

### Call metering

When the system receives charging information at outgoing calls from the public net, the STANDARD and EXECUTIVE telephones can activate cost indication and the elapsed charging data will be presented on the display.

For further information about Call Metering refer to Call Metering (141/155 34-ASB 150 02 Uen).

### Parking

1. Press external line key.

- Its lamp flashes slowly.
- Connected trunk will be parked automatically when another traffic function is selected.
- While trunk is parked, display shows PARKED CALL, unless another traffic function key is pressed.

### Reconnection of parked call

A parked call can be reconnected at any time:

1. Press external line key again.

- When a parked analogue trunk is reconnected, display always shows same information (trunk name and trunk number) irrespective of whether call is outgoing or incoming
- When a parked ISDN - trunk line is reconnected, the display will always show the number of the connected party.

See also under Parking - Individual (402/155 34-ASB 150 02 Uen) and “Parking - Common Access (401/155 34-ASB 150 02 Uen).

### Trunk line occupied by another extension user

As a trunk can have multiple representation, e.g. it can be represented on several different extension (system) telephones, the lamps of trunks that are occupied (being used) by other extensions will glow steadily.

It is not possible to connect a trunk in this state. Depression of the external line key results in busy tone and the display shows “BUSY or B”.

## Capacity

The maximum number of external line keys is only restricted by the number of programmable keys:

- BASIC DBC 210 = 3
- ECONOMYplus DBC 211 = 4
- STANDARD DBC 212 = 4
- EXECUTIVE DBC 213 = 14
- OPERATOR DBC 214 = 3
- KEY PANEL = 17

Old telephones:

- BASIC DBC 199 = 0
- ECONOMY DBC 601 = 0
- ECONOMY DBC 751 = 0
- STANDARD DBC 631 = 10
- STANDARD DBC 755 = 10
- EXECUTIVE DBC 662 = 30
- EXECUTIVE DBC 753 = 30
- OPERATOR DBC 663 = 20
- OPERATOR DBC 754 = 20

## Limitations

- A call established via an external line key and which is transferred will when the extension telephone receiving the transferred call be presented on Line 1 or Line 2.

- Consequently, one of these traffic functions must be free.

- External line key is not affected by activated diversion or follow me.

## Programming

0301 |  | Key function

0302 |  | Number/ID

0303 |  | Ringing alternative

See also under Ring and Tone Signals (443/155 34-ASB 150 02 Uen).

1101 |  | Answering position at day

3065 |  | Common hold

0101 |  | Facility COS

#### Individual programming

Extensions with digital telephones can program function keys for trunks.

See document Facility Description - General (155 34-ASB 150 02 Uen).

## Equipment

None

Revision: D © Ericsson Enterprise 2003