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Swiss PSTN

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Overview

This page aims to provide an overview of common pstn configurations in Switzerland. In Switzerland PSTN connectivity is provided by multiple carriers, mostly via ISDN. FXO is also provided but mostly to residential customers. SIP and H.323 Trunks are provided by some carriers.

 

Dialplan

The Swiss dialplan is a variable length numbering plan, which consists of area codes and subscribers numbers. Area Codes are 3 digits in length, subscriber numbers have 7 digits. Service Numbers have 3 or 4 digits. Some numbers (mostly used by companies) allow the use of Direct Inward Dial Extension. In this case, a direct dial code of 4-7 digits is assigned to the company, allowing extension number lengths of 2 to 5 digits. DDI numbers take the form 0 + DDI code + extension (exactly 10 digits in total).

 

A copy of the Swiss dialplan is maintained by the Swiss regulatory council at http://www.bakom.ch

The Swiss dial plan is available for CUCM. The name is "CHNP".

 

Emergency Services

The following emergency numbers are used:

112: General emergency service (equivalent to 911)
117: Police
118: Fire Department
144: Ambulance
145: Toxicological Information
1414: Emergency air services (REGA)
0333333333: Emergency air services (REGA)

 

The European emergeny number 112 works too.


Important information regarding emergency calls when implementing VoIP can be found:
http://www.bakom.admin.ch/org/grundlagen/00563/00564/00658/index.html?lang=de#
The documents listed on this page explain how routing can be changed by using prefixes (Leitweglenkung).

Private/PBX Dialplan

"0" is generally used as a trunk access code.

The area code must be provided for all calls to subscribers (not to service numbers).

 

Voice Interfaces and signalling

Physical Interfaces ISDN is the most common access technology for business pstn access.  Both BRI and PRI are available everywhere.

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):

 

interface BRI0/0/0
no ip address
isdn switch-type basic-net3
isdn point-to-point-setup
isdn incoming-voice voice
isdn reject vod
isdn static-tei 0
!-- DDI Interface. For MSN Interface leave it away.

Voice Port Config:

 

voice-port 0/0/0
translation-profile incoming TRANSLATION_IN
translation-profile outgoing TRANSLATION_OUT
compand-type a-law

ISDN Signalling

It's important to signal the proper ISDN plan/type. If this is not okay, the call may not come through and the numbers will not be shown correctly at the terminating phone (mobile).

 

Outgoing call

 

Mar  5 13:31:01.100: ISDN BR0/0/0 Q931: TX -> SETUP pd = 8  callref = 0x18 

        Bearer Capability i = 0x8090A3

               Standard = CCITT

               Transfer Capability = Speech 

               Transfer Mode = Circuit

               Transfer Rate = 64 kbit/s

       Channel ID i = 0x81

       Calling Party Number i = 0x0181, '3398'

               Plan:ISDN, Type:Unknown

       Called Party Number i = 0x81, '0566345xxx'

               Plan:ISDN, Type:Unknown


Outgoing call (using special agreement, necessary if A-number needs to be transfered on call forward, recommended)

 

Sep 24 14:19:52.456 MEST: ISDN Se0/0:15 Q931: TX -> SETUP pd = 8  callref = 0x1212
       Bearer Capability i = 0x8090A3
               Standard = CCITT
               Transfer Capability = Speech
               Transfer Mode = Circuit
               Transfer Rate = 64 kbit/s
       Channel ID i = 0xA9839F
               Exclusive, Channel 31
       Calling Party Number i = 0x2181, '264601xxx'
               Plan:ISDN, Type:National
       Called Party Number i = 0x81, '0719999xxx'
               Plan:ISDN, Type:Unknown

 

Incoming calls from the ISDN provider will have the type "unknown"

 

Sep 24 14:22:07.231 MEST: ISDN Se0/0:15 Q931: RX <- SETUP pd = 8  callref = 0x00F8
       Sending Complete
       Bearer Capability i = 0x8090A3
               Standard = CCITT
               Transfer Capability = Speech
               Transfer Mode = Circuit
               Transfer Rate = 64 kbit/s
       Channel ID i = 0xA9838D
               Exclusive, Channel 13
       Calling Party Number i = 0x0183, '0795556xxx'
               Plan:ISDN, Type:Unknown
       Called Party Number i = 0x81, '243'
               Plan:ISDN, Type:Unknown


The following translations help to adjust the numbers:

 

PSTN incoming: add a "0" to the calling number of the PSTN user

 

voice translation-rule 1
rule 1 /^0/ /00/

 

PSTN incoming: adjust called number to company dialplan

 

voice translation-rule 2
rule 1 /^.*\(......\)/ /\1/

 

PSTN outgoing: adjust calling number

 

voice translation-rule 3
rule 1 /^0\([1-9]\)/ /\1/ type any national
rule 2 /^00\([1-9]\)/ /\1/ type any national
rule 3 /^000\([1-9]\)/ /\1/ type any international

 

voice translation-profile TRANSLATION_IN
translate calling 1
translate called 2

voice translation-profile TRANSLATION_OUT
translate calling 3

Comments
alig.norbert
Enthusiast

How about a redirect call (using special agreement)? Do Swisscom need the redirect information? How does a proper debug output looks like?

Thanks,

Norbert

d.haeni
Enthusiast

At the local gateway, a redirected call looks no different than any other outgoing call. The only difference is the calling number IE that contains the original caller rather than a local DDI number.

As was pointed out above, Swisscom allows this kind of spoofing when the "special arrangement" option is ordered for the DDI.


Dec 15 15:09:45.271: ISDN Se0/0/0:15 Q931: TX -> SETUP pd = 8  callref = 0x50F2
        Bearer Capability i = 0x8090A3
                Standard = CCITT
                Transfer Capability = Speech 
                Transfer Mode = Circuit
                Transfer Rate = 64 kbit/s
        Channel ID i = 0xA98396
                Exclusive, Channel 22
        Calling Party Number i = 0x2081, '79XXXXXXX'
                Plan:Unknown, Type:National
        Called Party Number i = 0x80, '0566345xxx'
                Plan:ISDN, Type:Unknown

And for the sake of completeness: at a remote gateway, two calling number IEs can be observed for a redirected call: one with the "spoofed" original caller, and another one with the DDIs main number.

David

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