The present document specifies the second version of the Integrated Services Digital Network (ISDN) - Global System
for Mobile communications (GSM) Public Land Mobile Network (PLMN) signalling interface. The present document is
applicable to the interconnection of PLMN and ISDN.
The ISUP interface defined is the trunk signalling interface between the PLMN and the ISDN. It is assumed that the
interface between PLMN and ISDN can occur at any point in a national network, provided that the exchange in the
national network has this ISDN-PLMN signalling interface.
This signalling interface is based on ISUP version 2 (as given in ETS 300 356-1 to ETS 300 356-19 ([1] to [18])). The
functionality in the GSM system is based on GSM Phase 2.
NOTE 1: Support of new functionality in the GSM system applicable for this interface may be included in the
present document as amendments or be published as a new EN.
Connection types:
The following ISUP version 2 connection types can be supported:
- speech;
- 3,1 kHz audio;
- 64 kbit/s unrestricted;
- 64 kbit/s unrestricted preferred;
- 2 ´ 64 kbit/s unrestricted;
- 384 kbit/s unrestricted;
- 1 536 kbit/s unrestricted;
- 1 920 kbit/s unrestricted.
NOTE 2: 2 ´ 64 kbit/s, 384 kbit/s, 1 536 kbit/s, 1 920 kbit/s unrestricted and 64 kbit/s unrestricted preferred
connection types are not supported by the GSM access, however the connection types may be used in
order to support other access methods via the GSM network.
Supplementary services:
The following ISUP version 2 supplementary services can be supported:
- Calling Line Identification Presentation (CLIP)/Calling Line Identification Restriction (CLIR);
- Connected Line Identification Presentation (COLP)/Connected Line Identification Restriction (COLR);
- Terminal portability (TP);
- User-to-User Signalling (UUS);
- Closed User Group (CUG);
- Subaddressing (SUB);
- Malicious Call Identification (MCID);
- Confere (...abbreviated)