This page aims to provide an overview of common pstn configurations in Austria. In Austria PSTN connectivity is provided by multiple carriers, mostly via ISDN. FXO is only provided in very rare circumstances. SIP Trunks are provided by some carriers but are not widely available yet.
The Austrian dialplan is a variable length numbering plan, which consists of area codes and subscribers numbers. Area Codes are from 1 to 4 digits in length, subscriber numbers vary even more. Some Numbers (mostly used by companies) allow the use of Direct Inward Dial Extension. If such a number is used, it is up to the company to decide on the length of extensions, meaning that any length can be used.If too long extensions are used, the numbers might not be reachable from some sources. This is especially relevant with regard to number presentation inside of isdn, as stated under "Voice Interfaces and signalling".
The following emergency numbers are commonly used:
122: Fire Brigade
Generally it is preferred to make emergency service numbers accessible both directly as well as via the trunk access code (e.g. 0122)
"0" is generally used as a trunk access code, resulting in the following schemes:
0+Subscriber Number for local area code dialling
00+ Are Code+ Subscriber: Dialing to other area codes
000 + Country Code + Number: International Destinations
As mentioned before, the length of internal extensions is up to decision by the company which owns the PBX. This also translates to the dialplan. Generally the Attendant is reachable via 3 different ways. Consider the following example: A company has acquired the number +43 (1) 8676776 as their main office number. Then the receptionist / attendant would be reachable via the following
Dialing the Main Number without any extension, +43 1 8676776
Dialing the Main Number with "0" as the extension, +43 1 8676776 0
Dialing any number that is not defined inside of the pbx, e.g. numbers short or longer than the internal numbering plan of the company
Voice Interfaces and signalling
ISDN is the most common access technology for business pstn access. Both BRI and PRI are available and commonly used.
For ISDN BRI Interfaces, use "isdn switch-type basic-net3", for PRI Interfaces use "primary-net5"
Common ISDN BRI Int Config (Should work for most sites):
ISDN Overlap Sending and Receiving is commonly used in Austria. This poses some challenges with regard to the variable length dialplan is mentioned. The issue is further confounded, because ISDN Switches commonly only send the dialed extension without the main number.
Consider the following example, again using the number +43 1 867 67 76. Let's assume the customer is using 3 digit extensions. The following isdn setup might be received on a bri interface in austria:
Sep 22 19:52:07.336 MET: ISDN BR0/1/0 Q931: RX <- SETUP pd = 8 callref = 0x01 Sending Complete Bearer Capability i = 0x8090A3 Standard = CCITT Transfer Capability = Speech Transfer Mode = Circuit Transfer Rate = 64 kbit/s Channel ID i = 0x89 Exclusive, B1 Calling Party Number i = 0x2183, '69915600516' Plan:ISDN, Type:National
Even though no Called Party Number was transmitted, the setup is valid.
Such a setup could mean two things:
The Caller is calling the main number with the indent to speak to the receptionist
Further Digits will follow via isdn overlap receiving