External Call Restriction: Classes of Service

All telephone extensions (landline and DECT) are classified according to a hierarchy of levels ordered by their decreasing restrictions. The different codes represent the extent of restrictions on making direct-dialed telephone calls (e.g. internal calls only, local calls, or long-distance national calls). The external call restriction classes are as follows:

01 = internal calls only
02 = incoming and internal
04 = incoming, internal, and 0800 (standard) calls (including hallway phones) 
06 = local and vicinity calls
08 = Germany
09 = Germany and mobile
11 = Europe and USA
12 = Europe, USA, and mobile
13 = international
14 = international and premium-rate telephone numbers

If your extension does not allow an outgoing call, Operator Services can place that call for you. If you wish to have the existing extension configuration changed, please fill out and submit a request form (Auftragsformulare Telekommunikation). Emergency calls can be made from any extension. This also applies to calls made to University mobile phones. If the extension will not allow calls to a mobile phone (class 09), you must use the abbreviated dial function. There are two different abbreviated dial numbers (ADN), depending on the University mobile phone number:

Mobile: 0162 25237-XX
ADN: 950-237-XX

Mobile: 0162 25246-XX
ADN: 950-246-XX

Simply replace "XX" with the last two digits of the mobile phone telephone number.