The key characteristics of networks concerned are listed in table 2/09.06.
5.1 Characteristics of GSM PLMNs
The GSM PLMN is fully defined in the GSM series of specifications.
5.2 Characteristics of PSPDNs
These are defined in the relevant CCITT X series recommendations, such as X.1, X.2, X.10, X.25, and X.75.
5.3 Characteristics of ISDN
These are defined in the CCITT I‑series recommendations. The services and standards for the pan‑European ISDN are identified in ETR 010.
5.4 Characteristics of the packet service provided by the PH
The packet services supported via the packet handler interface (PHI) are defined in ETS 300 099. Support for both the ISDN X.31 Case A and Case B are specified there.
Table 2/GSM 09.06: Key characteristics of networks concerned
X.25, X.31, X.32
TE1 or TE2+TA)
see GSM 04.02
Information transfer mode
Cct or Packet
3.1 kHz audio
fax group 3, etc.
5.5 Characteristics of the packet service provided by a PH assuming the role of an AU or by X.32
The packet services provided by the PH assuming the role of an AU is defined in the ETS 300 099 (X.31 Case A). The packet service provided via a modem is defined in CCITT X.32.