3GPP43.045Release 16Technical realization of facsimile group 3 transparentTS
The mobile reference configurations described in this clause are defined as per 3GPP TS 24.002.
Figure 2/43.045: Reference configurations
The Teleservice definition in 3GPP TS 22.003 regards the group 3 facsimile terminal as a 2-wire analogue terminated equipment. In order to connect this to the MT2 a separate "Fax Adaptor" device is necessary.
This configuration, shown in figure 2a/43.045, has to be considered as the standard configuration, so that all the existing Group 3 facsimile apparatus can be connected to the PLMN.
An alternative realization would be to combine a standard group 3 facsimile machine and the Fax Adaptor into a specially developed "PLMN facsimile machine", directly providing a digital output. Although such a device must appear to the MT2 as identical to the Fax Adaptor (i.e. with an identical interface and protocol), it would allow for a significantly smaller and simpler facsimile machine. This configuration is shown in figure 2d/43.045 and is regarded as a desirable alternative.
In addition of course, it is always possible to realize an MT0, as per figure 2f/43.045, where both the facsimile and mobile termination functions are considered to be part of one integrated unit.
The remaining configurations concern the use of an S interface and are considered as optional configurations. Their use is for further study.
The particular terminal adaptation functions used are those detailed in 3GPP TS 27.003 and the interface to the MT2 used is synchronous V.24 with an option for support of V.25bis procedures for autocalling and autoanswering.
3.1 Fax Adaptor functionality
The Fax Adaptor block, figure 3/43.045, is intended to specifically complement the Group 3 facsimile apparatus in order to be able to communicate over a PLMN.
Figure 3/43.045: Fax Adaptor scheme
Whether it has to be a function internal to the PLMN, or an external accessory associated with the Group 3 apparatus, is beyond the scope of the present document, and in any case, does not affect at all the working of the procedure as here described.
It can be functionally partitioned in two sections:
– an analogue section, dealing with:
– the modulation and demodulation processes according to ITU-T Recommendation V.21, V.27ter, V.29 and V.17 as explained in T.4 and T.30;
– handling of the signalling on the 2-wire path to the facsimile machine, including autocalling and autoanswer functions where necessary (see clause 6).
– a digital section, dealing with:
– monitoring and where necessary, manipulation of the T.30 protocol as detailed in the rest of the present document;
– overall control of the adaptor;
– connection over the synchronous V.24 interface to the MT as described in 3GPP TS 27.003;
– where necessary, autocalling and autoanswering functions according to V.25bis.
In the following this specification will reference the Fax Adaptor functionality, considering the most general case where it operates as a full-featured (see figure 3/43.045) separate block (see figure 2a/43.045), as this reference configuration is implicitly or explicitly exhaustive of all service related technical aspects.
3.2 PLMN Facsimile Machine functionality
The special PLMN facsimile machine shown in the MS configuration of figure 2d/43.045 has a similar functionality to the digital part of the Fax Adaptor, but without any of the analogue portions.
It appears over the V.24 interface as identical to the Fax Adaptor, i.e. the MT2 needs to have no knowledge of the particular configuration used.
When necessary this reference configuration, will be explicitly referenced to in the following; otherwise all technical aspects relevant to the configuration implicitly apply.