5 Reference configuration at the mobile station

03.463GPPTechnical Realization of Facsimile Group 3 Service - non transparentTS

The mobile station reference configurations described in this clause are defined as per GSM 04.02.

<—————– Mobile station —————–>

╔═══════╗ 2-w ┌───────────┐ R ┌─────┐ :
a) ║ FAX ╟──┼──┤FAX Adaptor├──╫───────────────┤ MT2 ├─╫
╚═══════╝ └───────────┘ : └─────┘ :
: :
╔═══════╗ 2-w ┌───────────┐ R ┌──────┐ S ┌─────┐ :
b) ║ FAX ╟──┼──┤FAX Adaptor├──╫──┤ TA ├──╫──┤ MT1 ├─╫
╚═══════╝ └───────────┘ : └──────┘ : └─────┘ :
: :
╔═══════╗ 2-w ┌───────────┬──────┐ S ┌─────┐ :
c) ║ FAX ╟──┼─────┤FAX Adaptor│ TA ├─────╫──┤ MT1 ├─╫
╚═══════╝ └───────────┴──────┘ : └─────┘ :
: :
╔═══════╗ R : ┌─────┐ :
d) ║ FAX ╟────────────────────╫───────────────┤ MT2 ├─╫
╚═══════╝ : : └─────┘ :
: : :
╔═══════╗ R ┌──────┐ S ┌─────┐ :
e) ║ FAX ╟────────────────────╫──┤ TA ├──╫──┤ MT1 ├─╫
╚═══════╝ : └──────┘ : └─────┘ :
:
┌─────┐ :
f) │ MT0 ├─╫
└─────┘ :

Figure 2/03.46: Reference configurations

The teleservice definitions in GSM 02.03 regard the facsimile group 3 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/03.46, has to be considered as the standard configuration, so that all the existing facsimile group 3 terminals can be connected to the PLMN.

An alternative realization would be to combine a facsimile group 3 terminal and the fax adaptor into a special "GSM facsimile machine", directly providing a digital output. Although such a terminal must appear to the MT2 as identical as 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/03.46.

In addition of course, it is always possible to realize an MT0, as per figure 2f/03.46, 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 GSM 07.03 for non‑transparent bearer capability. The interface to the MT2 used is according to CCITT Recommendation V.24 with an option for support of CCITT Recommendation V.25bis procedures for auto calling and auto answering.

5.1 Fax adaptor functionality

The fax adaptor block, figure 3/03.46, is intended to specifically complement the facsimile group 3 terminal in order to be able to communicate over a GSM PLMN.

╔═══════════════════╤═══════════════════╗
║ │ ║
║ Composite │ ║
║ Modem │ Control, ║
2-w ║ │ Protocol ║ R
──┼──╫───────────────────┤ Monitoring ╟──╫──
║ │ & ║
║ Tone │ Buffer ║
║ Handling │ ║
║ │ ║
╚═══════════════════╧═══════════════════╝

Figure 3/03.46: Fax adaptor scheme

Whether it has to be a function internal to the GSM PLMN, or an external accessory associated with the facsimile group 3 terminal, is beyond the scope of the present document, and in any case, does not affect the working of the procedure as described here.

It can be functionally partitioned in two sections:

‑ an analogue section, dealing with:

‑ the modulation and demodulation processes according to CCITT Recommendation V.21, V.27ter, and V.29 as explained in CCITT Recommendation T.4 and T.30;

‑ handling of the signalling on the 2‑wire path to the associated facsimile terminal, including auto calling and auto answering functions where necessary (see clause 8).

‑ a digital section, dealing with:

‑ overall control of the adaptor;

‑ monitoring and, where necessary, manipulating the CCITT Recommendation T.30 protocol as detailed in the present document;

‑ connection to the MT using the interface according to CCITT Recommendation V.24 as described in GSM 07.03;

‑ buffering of facsimile data;

‑ transcoding of the CCITT Recommendation T.4 document content for transmission across the radio interface as detailed in the present document;

‑ where necessary, auto calling and auto answering functions according to CCITT Recommendation V.25bis.

5.2 GSM facsimile machine functionality

The special GSM facsimile machine shown in the MS configuration of figure 2d/03.46 is similar to the digital part of the fax adaptor, but without any of the analogue portions.

It appears at the CCITT Recommendation V.24 interface as identical as the fax adaptor, i.e. the MT2 needs to have no knowledge of the particular configuration used.