BusinessPhone Communication Platform 4.0
Facilities

## Trunk

## Definition

A trunk (tie-line) is a physical connection between ASB 150 02 and an external switching environment.

Trunks can be of type “analogue” or “digital”.

Trunks are used particularly for:

- Interworking with the public exchange (trunk)
- Interworking with other PBX (tie-line)

### Analogue trunks

Analogue trunks (four-eight line units per board) are used mainly for connection to old, analogue public exchanges.

Analogue trunks are also used for the connection of external paging equipment and music sources.

To minimise distortion on lines due to impedance mismatches the feature Automatic Trunk Impedance Adaption (ATIA) can be enabled via RASC for each trunk and tie line. This function adapts to the best possible impedance balance automatically.

See further under Programming of the ATIA feature.

The following analogue trunks are supported by ASB 150 02:

- BTU-A trunk (4-8 lines)
- BTU-A2 trunk (4-8 lines)
- BTU-C trunk (4 lines)
- BTU-E trunk (4 lines)

### Digital trunks

Digital trunks are used for connection to modern, digital public exchanges.

Digital (ISDN) trunks are also used for frame relayed data call connections to packet mode terminals.

The following digital trunks are supported by ASB 150 02

- 2Mb/s CAS trunk (1x30 B-channels)
- 2Mb/s ISDN PRA trunk (1x30 B-channels)
- 192kb/s ISDN BA trunk (8x2 B-channels)

For further information about ISDN-Trunks see (268/155 34-ASB 150 02 Uen).

### Directory numbers

On system start, each trunk is assigned automatically a directory number from 700 and upwards.

### Routes

Several trunks can be grouped in to a route(s) when the external destination/connection is the same for the trunks. A route is accessible with a route directory number to seizure one of the free trunks.

On system initiation are all the trunks on the first found trunk board placed in the route 0.

See also under ”Route Selection (444/155 34-ASB 150 02 Uen).

## Use

See also under ”Outgoing External Calls (381/155 34-ASB 150 02 Uen) and Incoming External Calls (262/155 34-ASB 150 02 Uen).

## Operation

See also under ”Outgoing External Calls (381/155 34-ASB 150 02 Uen) and Incoming External Calls (262/155 34-ASB 150 02 Uen).

## Capacity

The maximum number of trunks is determined by the number of available voice channels in the system, max. 61.

Analogue trunk boards: Maximum 7 boards (e.g. 7x8 lines = 56 lines).

Digital CAS or ISDN PRA trunk boards: Maximum 2 boards (2x30 B-channels = 60 lines).

Digital 2B+D boards: max. 3 full-equipped BTU-B2 boards (3x8 interfaces = 48 trunks), 7 sub-equipped BTU-B2 boards (7x4 interfaces = 56 trunks) or 7 MFU boards (7x4 interfaces = 56 trunks), whereby the later one does not make sence related to configuration and costs.

## Limitations

When dimensioning the system ensure that the number of trunks is in proportion with the number of available voice channels and also to the relationship between internal and external traffic.

In case of trunk to trunk connection (transit calls) where a proper call disconnection can not be ensured then the speech time is supervised and restricted to an approx. time of 10 minutes. This is depending of used line signal scheme (type of line disconnection signals) See further command 1201 Line signal scheme?.

## Programming

Each trunk line can be programmed for:

- adaptation of external call handling in the system
- adaptation of line signalling to a connected public exchange or other PBX

Note

Adaptation of transmission, line signalling and system times requires excellent knowledge of ASB 150 02 and the relevant signal scheme.

### Directory numbers

Via these commands it is possible to alter the number series for individual line positions or for all trunk lines.

5605 |  | Trunk directory number

5606 |  | Alter trunk directory number

5607 |  | Alter number series for trunk line

### Trunk categories

See also Categorisation (149/155 34-ASB 150 02 Uen).

The initial (default) parameter value for each category is stated below.

Depending of the searched effect of the external call handling, used signalling and type of trunk these parameters may be altered.

A more detailed category description is available as help text in RASC for each category.

Note

Not all categories are relevant for each type of trunk.

### Individual trunk parameters

#### Call handling parameters

These categories are the common call control and traffic parameters.

1001 |  | Facility COS

1002 |  | Traffic group

1003 |  | TCD-day COS

1004 |  | TCD-night COS

1005 |  | Common abbreviated number COS

1006 |  | Call back allowed ?

1007 |  | Break-in allowed ?

1008 |  | Camp-on to answering position ?

1014 |  | Result tones to parent exchange ?

1018 |  | Subsystem to PBX?

1020 |  | Pick up parked trunk?

1023 |  | Trunk line type

1029 |  | Tenant group

1201 |  | Line signal scheme?

### Monitoring times for call handling

1406 |  | Wait time before ringback/rerouting at not answered calls?

1407 |  | Maximum hold time

1408 |  | Minimum speech time for not increasing disturbance counter?

1409 |  | Time for recall on transfer before answer

1410 |  | Time for recall on camp-on

1417 |  | Length of external inquiry signal

1420 |  | Number of disconnection tone bursts

1421 |  | Pulse time for disconnection tone burst

1422 |  | Pause time for disconnection tone burst

### Outgoing traffic parameters

These categories are the outgoing call handling parameters.

1013 |  | Dial tone to extension?

1015 |  | Pre-digits for number analysis

See also Trunk Call Discrimination (487/155 34-ASB 150 02 Uen).

See also Least Cost Routing (321/155 34-ASB 150 02 Uen).

1028 |  | LCR analysis required?

1034 |  | Public dial tone to extension?

1036 |  | Type of IBERCOM netw. conn.

### Monitoring times for outgoing traffic

1416 |  | Blocking time for outgoing call after disconnection

1423 |  | Time supervision of B-answer

### Incoming traffic parameters

These categories are the incoming call handling parameters.

1022 |  | Voice info to trunk allowed ?

1031 |  | Answer by external line key allowed ?

1101 |  | Answering position at day?

1102 |  | Answering position at night?

See also Answer Position(s) For Trunks (112/155 34-ASB 150 02 Uen).

1105 |  | Common voice announcement at day

1106 |  | Common voice announcement at night?

1107 |  | Busy voice announcement at day

1108 |  | Busy voice announcement at night

1109 |  | Common voice announcement interruptable?

1801 |  | Common number at automatic outgoing/incoming traffic

1802 |  | Pre-digits at automatic incoming traffic

1803 |  | Irrelevant digits at automatic incoming traffic

1804 |  | DDI number translation

### Reroute conditions for incoming calls

An incoming call can be re-directed to a reroute position (in acc. to commands 1103, 1104) when the called party is in following states.

1009 |  | Reroute on answering position barred ?

1010 |  | Reroute on answering position blocked?

1011 |  | Reroute on answering position vacant?

1012 |  | Reroute on answering position busy?

1016 |  | Reroute on no answer ?

1017 |  | Reroute on incomplete number ?

1103 |  | Reroute position at day

1104 |  | Reroute position at night)

### Monitoring times for incoming traffic

1411 |  | Time supervision for first digit at automatic incoming traffic

1412 |  | Time supervision between digits at automatic incoming traffic

1413 |  | Time supervision of answer at automatic incoming traffic

1419 |  | Minimum supervision time between ringsignals

### Register signal parameters

These categories are the incoming and outgoing register signalling (decadic, DTMF, MFC, MFE, ISDN) parameters.

### General register signalling parameters

1307 |  | PTS-signal from parent exchange ?

1308 |  | PTS-signal from parent exchange = dial tone

1309 |  | PTS-signal from parent exchange = dial tone ?

1311 |  | Number of digits before EOS-signal

1314 |  | Type of dial tone receiver, TRC

1317 |  | Complete called party number length

### Decadic register signalling parameters

1301 |  | Incoming digit transmission

1302 |  | Outgoing digit transmission

1303 |  | Impulse type

1304 |  | Impulse frequency

1305 |  | Impulse ratio

1306 |  | Inter digit pause

### DTMF register signalling parameters

1024 |  | Simplified DISA at day?

1025 |  | Simplified DISA at night?

1301 |  | Incoming digit transmission

1302 |  | Outgoing digit transmission

1313 |  | DTMF signal scheme

### MFC register signalling parameters

1301 |  | Incoming digit transmission

1302 |  | Outgoing digit transmission

1312 |  | MFC signal scheme

1316 |  | Request A-number in MFC?

### MFE register signaling parameters

1301 |  | Incoming digit transmission?

1302 |  | Outgoing digit transmission?

1315 |  | MFE number plan for CLL?

### Monitoring times for register signalling

1401 |  | No of digits with long dial supervision?

1402 |  | Time supervision of long register signalling alt. MFC/MFE outgoing signalling?

1403 |  | Time supervision of short register signalling alt. MFC/MFE outgoing signalling?

1404 |  | Wait time before start to send digits when no PTS.

1414 |  | Length detection 1:st PTS?

1415 |  | Lenght detection 2:nd PTS?

### Metering parameters

These categories are the outgoing call handling parameters.

1501 |  | Call meter for trunk?

1502 |  | Tariff number?

1503 |  | Carrier number?

See also Call Metering (141/155 34-ASB 150 02 Uen).

### Monitoring times for metering

1405 |  | Wait time before metering is stopped?

1418 |  | Min. time for detection of call metering pulses?

### Transmission parameters

These categories are the hardware related (trunk, registers) transmission parameters. The usage is depending of the type of external call signalling.

1032 |  | Trunk Impedance Adaption

1033 |  | Impedance Adaption Transit

1601 |  | CEPT-DTMF tone receiver level?

1602 |  | ETOE-DTMF tone reveiver level?

1603 |  | Dial tone receiver level?

1604 |  | MFC-tone receiver level?

1605 |  | MFC tone sending level?

1606 |  | Disconn. tone receiver level?

1607 |  | Call meter type?

1608 |  | Call meter receiver level?

1609 |  | Filter coefficient?

1610 |  | Relative sending level?

1611 |  | Relative receiving level?

1612 |  | Transmission group?

1613 |  | Relative sending level during DTMF?

1614 |  | Call meter receiver level?

### Tie-line trunk signal parameters

These categories are related to the line signal schemes for analogue tie-line trunks. The usage is depending of the actual used line signal scheme.

1706 |  | Incoming traffic, Seizure acknowledge

1707 |  | Incoming traffic, PTS-signal

1708 |  | Incoming traffic, EOS-signal

1709 |  | Incoming traffic, Answering signal

1710 |  | Outgoing traffic, Seizure acknowledge

1717 |  | Outgoing traffic, Answering signal

1718 |  | Blocking on separate E2, M2 wires

### CAS-link Parameters

These categories are the CAS link and signalling parameters.

1901 |  | CRC-4 alarm conditions

### ISDN-link network interface parameters

These categories are the link and signalling parameters for a T-/Q-interface.

### ISDN link parameters

1910 |  | Interface type

1911 |  | Network signalling protocol

1912 |  | Termination in ASB 150

1913 |  | B-channel selection mode

1914 |  | Charging method

1915 |  | Provision of calling line identification

1916 |  | Overlap receiving of called party number

1917 |  | MCID activation request allowed

1918 |  | Provision of connected line identification

1919 |  | Assigned TEI value

1920 |  | CRC4 check

1921 |  | Ignore inband info at disconnection

1922 |  | Through connection after SETUP to net?

1940 |  | UUS services activation request

1941 |  | Explicit UUS service 1 activation request

1942 |  | UU-information length for UUS service 1

1943 |  | UU-information in ALERT message

1944 |  | Explicit UUS service 2 activation request

1945 |  | Explicit UUS service 3 activation request

1946 |  | Forced message after timeout

1947 |  | Handling of call collisions

1948 |  | CLIR Override at incoming calls

1949 |  | Carrier for proprietary services

### ISDN number plan

1925 |  | Pre-digit removal for E.164 number plan with unknown typ of number

1926 |  | Pre-digit removal for E.164 number plan with international typ of number

1927 |  | Pre-digit removal for E.164 number plan with national typ of number

1928 |  | Pre-digit removal for E.164 number plan with network specific typ of number

1929 |  | Pre-digit removal for E.164 number plan with local directory typ of number

1930 |  | Pre-digit removal for private plan with unknown typ of number

1931 |  | Pre-digit removal for private plan with Level 1 regional type of number

1932 |  | Pre-digit removal for private plan with Level 2 regional type of number

1933 |  | Pre-digit removal for private plan with Level 3 regional type of number

1934 |  | Pre-digit removal for private plan with PTN specific type of number

1935 |  | Pre-digit removal for private plan with local type of number

#### ISDN-link user interface parameters

These categories are the link and signalling parameters for a S-interface.

#### User parameters

1951 |  | Interface type

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 ?

1958 |  | Common access number

#### Assigned TEI values

1957 |  | Number restriction allowed from TEs ?

### Link supervision parameters

These categories are the general link syncronisation and link supervision parameters.

### Assignment of public numbers

These system categories are used to build up proper public calling/connected party (A-/B-party) numbers.

#### Public directory numbers

2220 |  | Public access number & Public area code

### Night service

This facility is used to divide the trunks in different night swching groups and thereby enable diffrent night answer positions for incoming calls.

See also Night Service (362/155 34-ASB 150 02 Uen).

The actual night swiching group (1-8) are referred by each trunk in acc. to command 1019.

## Equipment

Analogue trunk boards: BTU-A, BTU-A2, BTU‑C, BTU‑E

Digital trunk boards: BTU-D, BTU-B, MFU

Revision: E © Ericsson Enterprise 2003