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TR 27.901
Report on Terminal Interfaces: an Overview

Use "3GPP‑Page" to get the Word version, and "ETSI‑search" to get the PDF version
V5.0.0 (PDF)  2002/06  10 p.
V4.1.0  2002/03  10 p.
V3.1.0  2002/03  11 p.
Dr. Neal, Adrian

Content for  TR 27.901  Word version:  5.0.0

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1  ScopeWord‑p. 5
The present document discusses external and internal interfaces of a terminal, with the exception of the radio and USIM interfaces. The focus of the study has been on external interfaces, to identify where existing industry standards can be used and whether there would be a need for specifications to be produced within 3GPP.

2  References

The following documents contain provisions which, through reference in this text, constitute provisions of the present document.
  • References are either specific (identified by date of publication, edition number, version number, etc.) or non specific.
  • For a specific reference, subsequent revisions do not apply.
  • For a non-specific reference, the latest version applies. In the case of a reference to a 3GPP document (including a GSM document), a non-specific reference implicitly refers to the latest version of that document in the same Release as the present document.
No references were identified.

3  Definitions and abbreviations

3.1  Abbreviations

For the purposes of the present document, the following abbreviations apply:
AT Commands
ATtention Commands
Electronics Industry Association
Federal Communications Commission
International Electrotechnical Commission
Institute of Electrical and Electronics Engineers
Infrared Data Association
Integrated Services Digital Network
International Standardisation Organization
International Telecommunications Union - Telecom sector
Mobile Equipment
Mobile Termination
Radio Frequency
Terminal Adaptation
Terminal Equipment
Telecommunication Industry Association
Universal Asynchronous Receiver and Transmitter
Universal Serial Bus
Universal Subscriber Identity Module

4  Assumptions of the technical specification work for terminal interfacesWord‑p. 6

4.1  General

4.1.1  The 3GPP terminal model

The area of external and internal interfaces for 3GPP MEs have been studied and Figure 1 shows the model that has been used. The external interface, other than the radio and USIM interfaces, is the TE-MT/TA interface. An example of an internal interface is the TA-MT interface, as illustrated.
Reproduction of 3GPP TS 27.901, Figure 1: The 3GPP terminal model

4.1.2  Requirements

There is a vast variety of market expectations, depending on end-users' and operators' demands and needs, and the 3GPP terminal design choice must be made under full influence from these market requirements.
The goal is to find a way to minimize the time-to-market of new, evolved interface solutions, at the same time allowing for the widest possible service diversity, that can be provided by a variety of terminal designs.
The success of 3GPP requires that an efficient and flexible approach is found to give a timely and dynamic development of many kinds of terminals, each type optimized relative to its own specific target of market requirements, while at the same time not imposing restrictions on the global circulation of terminals.

4.2  Conclusions

It has been concluded that 3GPP should not produce any technical specifications for terminal interfaces (neither external, i.e. MT/TA-TE, nor internal, e.g. MT-TA) other than the radio interface and the USIM interface. This includes optional as well as mandatory mechanical, electrical and logical specifications for interfaces. As an exception, optional protocols that are necessary for 3GPP terminals and that are not defined elsewhere could be standardized. One agreed example is AT commands.
Instead of specifying external interfaces in 3GPP, appropriate open standards should be used for external interfaces for 3GPP terminals. A list of potential examples of such interfaces is shown in Table 1. It should be noted that the list of interfaces in Table 1 is not exhaustive and that new examples are likely to be added in the future as technical development advances. It should also be noted that proprietary external interfaces may be used in the 3GPP terminals. It is then up to the manufacturer to handle the adoption to standard interfaces.
Since the terminal external interfaces (other than the radio interface, the USIM interface and AT commands), are out of scope of 3GPP, the SDOs can develop their own physical connector specification based on their market requirements. Such specifications should be optional to allow for other terminal interface options to exist on those markets.

4.2.1  AT-commandsWord‑p. 7
One important aspect for 3GPP terminals is not being specified in any other specification forum, namely the AT commands. The AT commands are necessary for 3GPP terminals and should therefore be specified in 3GPP. AT commands can be commonly used as a common protocol specification, regardless of whether a wired or wireless connection (IR or RF) is used.
Most of the AT commands will be needed both in GSM and 3GPP. For this reason there is a need to have full access in 3GPP to the GSM defined AT commands.

5  Examples of external interfaces

Below some potential examples of external interface specifications are given.
Interface Standard Physical Media (connector) Data Rate Network Topology Standard
EIA-232FNine wiresUp to 115 kbpsPoint to pointTIA/EIA-232-F
UART (Intel 8251A Industry Standard)
EPP Enhanced Parallel PortIEEE 1284 -connector with 25 or 36 wiresUp to 1,5 MbpsPoint to pointIEEE Std 1284-1994
ISDN S-InterfaceEight wires2X64 kbps + 16 kbpsPoint to pointISO/IEC 8877:1992
ITU-T Recommendation I.430
IEEE 802.3 EthernetFour wires10 MbpsMultimasterISO/IEC 8877:1992
IEEE Std. 802.3 1998 Edition
USBFour wires (USB Connector)Up to 12 MbpsMaster to slave devicesUSB Specification 1.1
IEEE 1394Four wires (iLink connector)100 Mbps - 400 MbpsMultimasterIEEE Std. 1394 - 1995
IrDA-SIRInfra red transceiver (line of sight)Up to 115 kbpsPoint to point(s)Infrared Data Association Serial Infrared
Physical Layer Specification v1.3
IrDA-MIRInfra red transceiver (line of sight)Up to 1 MbpsPoint to point(s)Infrared Data Association Serial Infrared
Physical Layer Specification v1.3
IrDA-FIRInfra red transceiver (line of sight)Up to 4 MbpsPoint to point(s)Infrared Data Association Serial Infrared
Physical Layer Specification v1.3
802.11 - IRInfra red transceiver (diffused IR)Up to 2 MbpsMultimasterIEEE Std 802.11-1997
802.11-FHSSFrequency-Hopping Spread Spectrum RFUp to 2 MbpsMultimasterIEEE Std 802.11-1997
802.11- DSSSDirect Sequence Spread Spectrum RFUp to 2 MbpsMultimasterIEEE Std 802.11-1997
BluetoothFrequency-Hopping Spread Spectrum RF721 kbs + 57,6 kbs or 2x432,6 kbsPoint to point(s)Bluetooth Specification 1.0

$  Change HistoryWord‑p. 8

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