15.1 Basics for the ISDN connection
Before setting up an ISDN trunk in Swyx Administration, you must install the ISDN card.
There are various connection types that service providers distinguish when providing the service; see PSTN Access. There are also different operating modes on the Swyx itself; see Connection Types for the ISDN Lines.
Connection Types for the ISDN Lines
The lines of an ISDN card can be used in different ways.
Operation Directly with the Public ISDN
In this configuration, the ISDN card is operated directly with an ISDN connection to the public telephone network (PSTN).
Operation with an Existing Telecommunication System as a Sub-telecommunication System
In this case, there is a PBX system that is connected to the PSTN, and the ISDN card is connected to this PBX system. In this case, Swyx is a sub-PBX; Swyx does not have direct access to the PSTN.
Operation as a Main System with a Sub-telecommunication System
Swyx has a connected sub-PBX, and the line to be configured connects the main PBX and the sub-PBX.
PSTN Access
Furthermore, there is a difference between a PSTN connection, which has a line with one line number and an extension range, and one which has one line with several MSNs.
Operation with One Line Number and Extension Range
In this configuration, the ISDN card is operated with a direct dialing-in ISDN line. This connection is assigned a phone number. An extension range is defined in addition to this number ( The "Numbers" Tab). Each Swyx user can now be assigned one or more numbers from this extension range. A subscriber's complete telephone number is then e.g. composed of the phone number and the extension number.
Example:
Phone number 12345, subscriber number 777
-> Number 12345777
Operation with One Line with Several MSNs
When this configuration is used, it is possible to operate the ISDN card simultaneously with other ISDN devices using a common connection. When connecting using MSNs, one or more MSNs are assigned to the ISDN trunk in the configuration. Accordingly, Swyx processes only calls directed to these MSNs. This makes it possible to assign additional numbers to other terminal equipment such as a fax machine. The MSNs specified in the configuration can be assigned to Swyx users as desired. Since, to be unique, an MSN can only be assigned to exactly one user, the maximum number of users is limited by the number of available MSNs. Because the maximum number of MSNs is usually 10, this configuration is only recommended for smaller systems.
Operation with a Basic Rate Interface (BRI)
The Basic Rate Interface (BRI) provides 2 channels. Your provider can supply you with one line or with a line with several MSNs for your line connection.
The ISDN card SX2 QuadBRI can operate up to four Basic Rate Interfaces.
Operation with a Primary Multiplex Access (PRI)
A Primary Rate Interface (PRI) is always a direct dialing-in line. In contrary to a Basic Rate Interface (BRI) with 2 available channels, it supplies a maximum of 30 available channels.
A Group of Connections - Line Group
If the number of available channels is not sufficient, several lines can be combined in order to increase capacity. Both the switching center and Swyx treat this group of extensions as a single extension with a higher number of channels. A line with a free channel will be searched for automatically. This takes place in a way which is fully transparent for the user and it does not require any additional configuration.