scope:

This standard defines the stage one of the Terminal Portability (TP) supplementary services for the pan- European Integrated Services Digital Network (ISDN) as provided by European public telecommunications operators. Stage one is an overall service description from the user's point of view, but does not deal with the details of the human interface itself (see CCITT Recommendation I.130 [1].

 This standard defines the interworking requirements of private ISDNs with the public ISDN.

In addition this standard specifies the base functionality where the service is provided to the user via a private ISDN.

This standard does not specify the additional requirements where the service is provided to the user via a telecommunications network that is not an ISDN but does include interworking requirements of other networks with the public ISDN.

Interactions with supplementary services not listed in clause 8 are outside the scope of this standard.

Charging principles are outside the scope of this standard.

The (TP) supplementary service allows a user to move a terminal from one socket to another within one given basic access during the active state of a call.

The portability of a terminal during the idle state is part of the basic access capabilities and does not require any procedure.

The portability of a terminal in the call establishment and in the call clearing phases is not possible.

The TP supplementary service applies to some interactive circuit-switched telecommunication services requiring the attendance of a human being, such as telephony, videotelephony, etc.

However, the network will not take any action to restrict its applicability.

The relative terminals should provide at the man/machine interface the capabilities for:

- suspension of the call(s)

- resumption of the call(s)

- indication of the phase of the call(s) (i.e. active phase and suspended phase) as long as the terminal ramains plugged in.

The TP supplementary service does not apply to non-interactive services such as facsimile, teletex, mixed-mode, computer communication etc. The relative terminals should not provide for the above mentioned capabilities.

It is a user's responsibility to resume the call with a terminal which is compatible both with the remote terminal and with the type of connection previously established.

This standard is aplicable to the stage two and stage three standards for the ISDN TP supplementary service. The terms "stage two" and "stage three" are also defined in CCITT Recommendations I.130 [1] Where the text indicates the status of a requirement, i.e. as strict command or prohibition, as authorisation leaving freedom, as a capability or possibility, this shall be reflected in the text of the relevant stage two and stage three standards.

Furthermore, conformance to this standard is met by conforming to the stage three standards with the field of application appropriate to the equipment being implemented. Therefore no method of testing is provided for this standard.