ETSI TR 102 021-9 V1.1.1 (2009-04)

Technical Report
Terrestrial Trunked Radio (TETRA);
User Requirement Specification TETRA Release 2;
Part 9: Peripheral Equipment Interface

2 ETSI TR 102 021-9 V1.1.1 (2009-04)

Reference
DTR/TETRA-01180
Keywords
TETRA, user, MS, radio
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3 ETSI TR 102 021-9 V1.1.1 (2009-04)
Contents
Intellectual Property Rights . 5
Foreword . 5
Introduction . 5
Background . 6
Need for a Physical Link Update . 6
1 Scope . 7
2 References . 7
2.1 Normative references . 7
2.2 Informative references . 8
3 Definitions and abbreviations . 8
3.1 Definitions . 8
3.2 Abbreviations . 9
4 Background . 10
4.1 Support of High Data Rates . 10
4.2 Data Reliability . 10
4.3 Power Efficiency . 10
4.4 Robustness . 10
4.5 Ease-of-Use . 10
4.6 Widely Adopted in the Information Technology World and Compatibility with Other Data Systems . 10
4.7 Security . 10
5 Wired Solutions - Background . 11
5.1 Firewire . 11
5.1.1 Technical Specification and Architecture . 11
5.1.2 Power Supply . 11
5.1.3 Versions and Data Rates . 11
5.1.3.1 Firewire 400 . 11
5.1.3.2 Firewire-800 . 12
5.2 USB . 12
5.2.1 Technical Specification and Architecture . 12
5.2.2 Power Supply . 12
5.2.2.1 Versions and Data Rates . 12
5.2.2.1.1 USB 1.0/1.1 . 12
5.2.2.1.2 USB 2.0 . 13
5.2.3 USB Backward Compatibility . 13
5.3 USB on the Go . 13
5.3.1 Why USB OTG . 13
5.3.2 Power Supply . 14
5.3.3 USB Data Transfer Modes, Connection Configurations . 14
5.3.3.1 Control transfers . 14
5.3.3.2 Interrupt transfers . 14
5.3.3.3 Isochronous transfers . 14
5.4 EIA-485 . 15
5.4.1 Technical Specification and Architecture . 15
5.4.2 Power Supply . 15
5.5 Comparisons between Wired Solutions . 16
5.5.1 Support of High Data Rates . 16
5.5.2 Data Reliability . 16
5.5.3 Power Efficiency . 16
5.5.4 Robustness . 16
5.5.5 Ease-of-Use. 17
5.5.6 Widely Adopted in the Information Technology World and Compatibility with Other Data Systems . 18
5.5.7 Data overhead . 18
6 Wireless Solutions - Background . 19
6.1 Wireless USB . 19
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4 ETSI TR 102 021-9 V1.1.1 (2009-04)
6.1.1 Certified Wireless USB (CWUSB) . 19
6.1.2 CWUSB Technical Specification and Architecture . 19
6.1.3 Versions and Data Rates . 19
6.1.4 UWB Noise . 19
6.2 Bluetooth . 19
6.2.1 Technical Specification and Features . 20
6.2.2 Versions, Features and Data Rates . 20
6.3 Infrared Data Association . 20
6.3.1 Technical Specification and Features . 21
6.3.2 Versions, Features and Data Rates . 21
6.4 Comparisons between Wireless Solutions . 21
6.4.1 Support of High Data Rates . 21
6.4.2 Data Reliability . 22
6.4.3 Power Efficiency . 22
6.4.4 Robustness . 22
6.4.5 Ease-of-Use. 22
6.4.6 Widely Adopted in the Information Technology World and Compatibility with Other Data Systems . 23
6.4.7 Security . 23
7 Background Conclusions . 25
7.1 Comparison of technologies . 25
7.1.1 Summary of table 7.1 . 25
7.1.2 Summary of table 7.2 . 25
8 User Requirements for Enhancements of the TETRA Peripheral Equipment Interface standard . 26
8.1 Introduction . 26
8.2 Physical Link . 26
8.2.1 USB . 26
8.2.2 Bluetooth . 26
8.2.3 Wireless USB. 27
8.3 Multimedia capability . 27
8.4 QoS negotiation . 27
8.5 Circuit mode data, SDS, and STATUS messaging . 27
8.6 Multiple services on PEI . 27
8.7 Void . 27
8.8 Multiple applications . 27
8.9 Embedded systems . 28
8.10 Legacy applications support (TETRA and GSM) . 28
8.11 Standardized complete support similar by all manufacturers . 28
8.12 Interoperable . 28
8.13 Developing a driver from scratch . 28
8.14 Multiple platforms . 28
8.15 Ease of application developers . 28
8.16 Circuit mode data, PD, SDS and STATUS messaging . 28
8.17 Minimum cost . 29
8.18 Time to market . 29
8.19 Open source driver layers . 29
8.20 Freely available drivers . 29
8.21 IPR licensing costs - FRAND. 29
8.22 Resilient to errors on the interface . 29
8.23 Future upgradeability . 29
8.24 Hot-pluggable . 30
8.25 Easy to test and certify . 30
8.26 Low CPU and memory overhead . 30
8.27 Battery life concerns . 30
8.28 Flow control . 30
Annex A: Indicative data throughput rates for example TETRA 2 data applications. . 31
A.1 Data rates . 32
Annex B: Comparisons between data format, number of supported devices, maximum data
speed and usage of well-known physical links . 33
History . 34
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5 ETSI TR 102 021-9 V1.1.1 (2009-04)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in ETSI SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in
respect of ETSI standards", which is available from the ETSI Secretariat. Latest updates are available on the ETSI Web
server (http://webapp.etsi.org/IPR/home.asp).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in ETSI SR 000 314 (or the updates on the ETSI Web
server) which are, or may be, or may become, essential to the present document.
Foreword
This Technical Report (TR) has been produced by ETSI Technical Committee Terrestrial Trunked Radio (TETRA).
The present document is part 9 of a multi-part deliverable covering the User Requirement Specification TETRA
Release 2 and Release 2.1, as identified below:
Part 1: "General overview";
Part 2: "High Speed Data";
Part 3: "Codec";
Part 4: "Air Interface Enhancements";
Part 5: "Interworking and Roaming";
Part 6: "Subscriber Identity Module (SIM)";
Part 7: "Security";
Part 8: "Air - Ground - Air services";
Part 9 "Peripheral Equipment Interface";
Part 10: "Local Mode Broadband";
Part 11: "Over The Air Management".
Introduction
The Terms of Reference for TC TETRA approved at ETSI Board meeting #52, May 2005 ([ETSI/B52(05)13 rev.1]) is
to produce ETSI deliverables (and maintenance thereafter) in accordance with the following requirements:
• The provision of user driven services, facilities and functionality as required by traditional Professional Mobile
Radio (PMR) user organizations such as the Emergency Services, Government, Military, Transportation,
Utility and Industrial organizations as well as Public Access Mobile Radio (PAMR) Operators.
• The evolution and enhancement of TETRA as required by the market with the provision of new services,
facilities and functionality made possible by new technology innovations.
• Further enhancements of the TETRA air interface standard in order to provide increased benefits and
optimization in terms of spectrum efficiency, network capacity, system performance, quality of service, and
other relevant parameters.
• The full backward compatibility and integration of the new services, facilities and functionality with existing
TETRA standards in order to future-proof the existing and future investments of TETRA users.
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6 ETSI TR 102 021-9 V1.1.1 (2009-04)
The TETRA Release 2 standard, incorporating the high-speed capability (TEDS) has just been published. This
high-speed data capability increases the maximum data rate of the TETRA systems from 28,8 kbit/s to over 500 kbit/s,
which has the capability to radically changing the range of data applications available to TETRA users. The current
TETRA PEI standard, EN 300 392-5 [i.18] V1.3.1 is a narrow band interface with limited application handling
capability for the Release 2 type TETRA networks. Hence, an enhanced PEI with a concurrent multimedia capability is
essential to enable access to the system from a range of data terminals (such as laptops, etc.).
The present document provides the User Requirement Specifications for the TETRA Peripheral Equipment Interface
enhancements.
The URS is required by WG3 and WG4 of TC TETRA to guide the enhancement of the current TETRA PEI standard.
Background
The PEI standard which was last updated on August 2007 EN 300 392-5 [i.18], defines a point-to-point configuration
between a TE2 and a MT2 using a sub-set of ITU-T Recommendations V.24 [i.2] and V.28 [i.3]. The V.24 standard
provides list of definitions for interchange circuits between Data Terminal Equipment (DTE) and Data
Circuit-Terminating Equipment (DCE), first agreed in 1964 which is equivalent to a subset of Electronic Industries
Association (EIA) Recommended Standard EIA-232. Beside large voltage swings, limitations in noise immunity and
low reliability of the flow control mechanisms that this standard introduces, the achievable data rate is also a major
bottleneck in wide-band capability of the TETRA release 2.
In order to propose appropriate physical links, an initial study has already been carried out by HW communications Ltd
and submitted to ETSI TC TETRA WG4 as a response to the ETSI's call for STF 314 on TETRA Release 2 PEI [i.4].
The present document, recommends wired and wireless physical link candidates that should be used between a
Terminal Equipment 2 (TE2) and a Mobile Termination 2 (MT2) at the TETRA reference point RT [i.1].
Need for a Physical Link Update
Before the initiation of TETRA Release 2, limited attention has been paid to the provision of IP-based wideband
multimedia services in Private Mobile Radio (PMR) wireless networks, such as those used by public safety
organizations in TETRA release 1. However, TETRA Release 2 has changed this by development of TEDS, which
intends to broaden the spectrum of multimedia services offered to TETRA users. As TEDS offers data rates comparable
to that of 2,5G/3G networks, then the using real-time multimedia applications will be feasible in TETRA.
For example, in table 1, the average required throughput for real-time video is presented. The video resolution and
frame sizes are derived based on ITU-T Recommendation H.264 [i.5]. It is clear that for TETRA2, using outdated
physical link technologies such as EIA-232 which supports maximum data rate of 20 kbit/s is no longer a feasible
option.
Table 1: Average throughput for real-time video transmission
Multimedia service Average throughput (kbit/s)
Real-time video (Resolution/frame)
128 × 96 / 30,9 64
176 × 144 / 15,0
176 × 144 / 30,3 192
320 × 240 / 10,0
A list of applications with minimum required data rates for transmission is provided in annex A.
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7 ETSI TR 102 021-9 V1.1.1 (2009-04)
1 Scope
The present document provides the User Requirement Specifications (URS) for the enhancements of the TETRA
Peripheral Equipment Interface.
The existing TETRA PEI standard has been available since 1998. The TETRA Release 2 standard, incorporating the
high-speed data capability (TEDS) has been published. This HSD capability increases the maximum data rate of the
TETRA systems from 28,8 kbit/s to over 500 kbit/s, radically changing the range of data applications available to
TETRA users. The TETRA users could, from now on, use a range of multimedia applications (with video as a medium)
via TEDS channels. One bottleneck to making full use of this new capability is the restrictions imposed by interfacing
TETRA Release 2 systems via mobile stations only. Hence, a standard HSD PEI with a concurrent multimedia
capability is essential to enable access to the system from a range of data terminals (such as laptops, etc.).
Peripheral Equipment Interface enhancements translated into terms of:
• PEI physical layer aspects;
• Multimedia capability ;
• QoS negotiation
The present document is applicable to the specification of TETRA Release 2 equipment.
The user requirements contained in the present document are described mainly in non-technical terms and are based on
discussions in TC TETRA WG1.
2 References
References are either specific (identified by date of publication and/or edition number or version number) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• Non-specific reference may be made only to a complete document or a part thereof and only in the following
cases:
- if it is accepted that it will be possible to use all future changes of the referenced document for the
purposes of the referring document;
- for informative references.
Referenced documents which are not found to be publicly available in the expected location might be found at
http://docbox.etsi.org/Reference.
NOTE: While any hyperlinks included in this clause were valid at the time of publication ETSI cannot guarantee
their long term validity.
2.1 Normative references
The following referenced documents are indispensable for the application of the present document. For dated
references, only the edition cited applies. For non-specific references, the latest edition of the referenced document
(including any amendments) applies.
Not applicable.
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8 ETSI TR 102 021-9 V1.1.1 (2009-04)
2.2 Informative references
The following referenced documents are not essential to the use of the present document but they assist the user with
regard to a particular subject area. For non-specific references, the latest version of the referenced document (including
any amendments) applies.
[i.1] ETSI TR 102 021-1: "Terrestrial Trunked Radio (TETRA); User Requirement Specification
TETRA Release 2; Part 1: General Overview".
[i.2] ITU-T Recommendation V.24: "List of definitions for interchange circuits between data terminal
equipment (DTE) and data circuit-terminating equipment (DCE)".
[i.3] ITU-T Recommendation V.28: "Electrical characteristics for unbalanced double-current
interchange circuits".
[i.4] Collective Letter 06-2474 (2006-06): "Preliminary Call for Experts for Specialist Task Force QH
(ETSI/ TETRA WG4) on TETRA Release 2 Peripheral Equipment Interface (PEI)".
[i.5] ITU-T Recommendation H. 264: "Advanced video coding for generic audiovisual services".
[i.6] 1394 Trade Association, "1394 Standards and Specifications Summary".
[i.7] Universal Serial Bus.
NOTE: Available at http://www.usb.org.
[i.8] "On-The-Go Supplement to the USB 2.0 Specification".
NOTE: Available at http://www.usb.org/developers/onthego/.
[i.9] "Engineering Department, Electronic Industries Association, EIA Standard RS-485 Electrical
Characteristics of Generators and Receivers for Use in Balanced Multipoint Systems, reprinted in
Telebyte Technology "Data Communication Library" Greenlawn NY, 1985".
[i.10] http://www.bulgin.co.uk.
[i.11] "Wireless Universal Serial Bus Specification" 1.0 Revision by: Agere Systems Inc.,
Hewlett-Packard Company, Intel Corp., Microsoft Corp., NEC Corp., Koninklijke Philips
Electronics N.V., Samsung Electronics Co. Ltd., May 2005.
[i.12] http://www.wimedia.org/en/index.asp.
[i.13] http://www.cypress.com/.
[i.14] "Specification of the Bluetooth system", Specification Version D, November 2004.
[i.15] http://www.irda.org/.
[i.16] http://www.wi-fi.org/.
[i.17] ITU-T recommendation V.250: "Serial asynchronous automatic dialling and control".
[i.18] ETSI EN 300 392-5: "Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D);
Part 5: Peripheral Equipment Interface (PEI)".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of the present document, the following terms and definitions apply:
function: entity, especially in USB OTG, that is responsible for responding to requests to initiate communications on
the PEI
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9 ETSI TR 102 021-9 V1.1.1 (2009-04)
host: entity, especially in USB OTG, that is responsible for initiating the communications on the PEI
3.2 Abbreviations
For the purposes of the present document, the abbreviations apply:
ASN Abstract Syntax Notation
BER Bit Error Rate
COM COMmunications (serial) port
CPU Central Processing Unit
CWUSB Certified Wireless USB
DSCP DiffServ CodePoints
EIA Electronics Industries Association (USA).
EISA Extended ISA
FCC Federal Communications Commission (USA)
FRAND Fair, Reasonable And Non-Discrimatory terms.
GFSK Gaussian Frequency Shift Keying
GPL GNU Public License
GSM Groupe Special Mobile
HSD High-Speed Data
IETF Internet Engineering Task Force
IOP InterOPerability
IP Internet Protocol or International Protection
IrDA Infrared Data Association
IRQ Interrupt ReQuest
ISA Industry Standard Architecture
ITU-T International Telecommunications Union - Telecommunications standardization sector
mA milliAmpere
MIDI Musical Instrument Digital Interface
MS Mobile Station (which comprises both TE and MT)
MT Mobile Terminal
OSI-RM Open System Interconnection – Reference Model
PC Personal Computer
PCI Peripheral Connection Interface
PD Packet Data
PDA Personal Digital Assistant
PEI Peripheral Equipment Interface
PPP Point-to-Point Protocol
QoS Quality of Service
RF Radio Frequency
SCSI Small Computer Systems Interface
SDS Short Data Service
SNR Signal to Noise Ratio
STATUS When capitalized, this means TETRA 16-bit status messaging
TCP Transport Control Protocol
TE Terminal Equipment, which is used for hosting an application
TEDS TETRA Enhanced Data Service
TETRA TErrestrial Trunked RAdio
UART Universal Asynchronous Receiver / Transmitter
UDP User Datagram Protocol
USB OTG USB On The Go
USB Universal Serial Bus
UWB Ultra WideBand
WiFi Wireless Fidelity
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4 Background
There are number of criteria to be considered for a suitable physical link. The following criteria are briefly explained.
4.1 Support of High Data Rates
This is a prime requirement that enables wideband transmission of concurrent applications including multimedia.
4.2 Data Reliability
The physical link should provide minimum acceptable data reliability. This is an important feature that almost all
applications such as multimedia data rely upon. Unreliable communication does not only affect the data and data quality
but also affects the throughput.
4.3 Power Efficiency
Low power physical links which results in longer battery life and connection time of a mobile unit as well as the
peripheral equipment is an important factor.
NOTE: It is not straight forward to calculate power efficiency of physical links. This is because almost all
chipsets have different operation modes such as "Active or Operating" and "Suspend" modes. Depending
on the application''s data rate and times switching between operating and suspend mode, power
consumption changes are non trivial to calculate.
It is possible to introduce a function that takes parameters based on the application and derive power consumption of
chipsets. Let us consider two parameters as α and β representing percentage of the time that device is in operating or
suspended mode, respectively. Then mean power consumption, P , of the chipset is defined as:
C
P = α × P + β × P
C A S (Eq.1)
Where, P and P are power consumption of the chipset in operating and suspended modes respectively.
A S
4.4 Robustness
The physical link should be robust in harsh environments and protect itself from ingress of hazards such as water, oil
and dust. The same time connection should be stable and reliable in harsh conditions such as on-the-move, vibration
intensive, scenarios.
4.5 Ease-of-Use
In emergency situations, the user should be able to setup and disconnect a physical connection fast and effectively.
4.6 Widely Adopted in the Information Technology World and
Compatibility with Other Data Systems
This is to ensure cost effective, easy and efficient implementation and operations. It is important to ensure that the
physical connection is supported by most peripheral equipment such as PCs, video conferencing units, telemedicine
platforms and portable clinical devices.
4.7 Security
For wireless solutions, data security is an important issue. The proposed physical links would be compared together
where the level of securities that they provide are rated.
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11 ETSI TR 102 021-9 V1.1.1 (2009-04)
5 Wired Solutions - Background
5.1 Firewire
Many computers intended for home or professional audio/video use built-in FireWire [i.6] interfaces.
The Firewire documentation defines a media, topology and protocol for a point-to-point serial cable interface.
5.1.1 Technical Specification and Architecture
The digital interface supports either asynchronous or isochronous data transfers. FireWire can connect together up to
63 peripherals in an acyclic topology (as opposed to Parallel SCSI's Electrical bus topology). It allows peer-to-peer
device communication to take place without using system memory or the CPU. FireWire also supports multiple hosts
per bus. It is designed to support Plug-and-play and hot swapping. Its six-wire cable is more flexible than most Parallel
SCSI cables and can supply up to 45 watts of power per port at up to 30 volts, allowing moderate-consumption devices
to operate without a separate power supply.
5.1.2 Power Supply
Based on the electrical specification of a chipset (µPD72852A with data sheet number: S16725EJ2V0DS),
recommended operating voltage and current are presented in tables 5.1 and 5.2.
Table 5.1: Power supply voltage
Parameter Condition MIN. TYP. MAX. Unit
Power supply voltage Source power node 3,0 3,3 3,6 V
Non-source power node 2,7 3,0 3,6 V

Table 5.2: Power supply currents
Parameter Condition TYP. Unit
Supply Current Transmit maximum packet (all ports transmitting maximum 68 mA
size isochronous packet - 4 096 bytes, sent on
every isochronous interval, S400), V = 3,3 V,T = 25° C
A
Repeat typical packet (receiving on one port DV packets on 60 mA
every isochronous interval, S100, and transmitting on the
other port), VDD = 3,3 V, TA = 25° C
Idle (one port receiving and one port transmitting cycle 40 mA
starts), VDD = 3,3 V, TA = 25° C
1 port receiving cycle start packet only, V = 3,3 V, TA=25° C 31 mA
Suspend mode, V = 3,3 V, TA = 25° C 115 mA

NOTE: Exact power supply and power efficiency depends on the chipset and manufacturer. In the present
document, we have selected one chipset for each physical link.
5.1.3 Versions and Data Rates
5.1.3.1 Firewire 400
Firewire 400 can transfer data between devices at 100 Mbit/s, 200 Mbit/s or 400 Mbit/s data rates. These different
transfer modes are commonly referred to as S100, S200, and S400. Cable length is limited to 4,5 meters (about 15 feet),
although up to 16 cables can be daisy chained using active repeaters, external hubs, or internal hubs often present in
Firewire equipment.
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12 ETSI TR 102 021-9 V1.1.1 (2009-04)
5.1.3.2 Firewire-800
FireWire-800 was introduced commercially by Apple in 2003. This newer specification and corresponding products
allow a transfer rate of 786,432 Mbit/s with backwards compatibility to the slower rates and 6-pin connectors of
FireWire 400.
Table 5.3: FireWire-800 data rates as a function of distance
Cable type 100 Mbps 200 Mbps 400 Mbps 800 Mbps 1 600 Mbps 3 200 Mbps
9-pin shielded twisted pair copper 4,5 m 4,5 m 4,5 m 4,5 m 4,5 m 4,5 m
CAT 5 unshielded twisted-pair 100 m - - - - -
Step-index plastic optical fibre 50 m 50 m - - - -
Polymer-clad plastic optical fibre 100 m 100 m - - - -
Glass optical fibre 100 m 100 m 100 m 100 m 100 m 100 m

5.2 USB
Universal Serial Bus (USB) [i.7] is a connectivity specification developed by Intel and other technology industry
leaders. USB provides ease of use, expandability, and speed for the end user. USB is arguably the most successful
interconnect in computing history. USB was designed to allow peripherals to be connected without the need to plug
expansion cards into the computer's ISA, EISA, or PCI bus and to improve plug-and-play capabilities by allowing
devices to be hot-swapped. When a device is first connected, the host enumerates, recognizes it, and loads the
appropriate device driver as required.
5.2.1 Technical Specification and Architecture
A USB system has an asymmetric design, consisting of a host controller and multiple daisy-chained devices. Additional
USB hubs may be included in the chain, allowing branching into a tree structure, subject to a limit of 5 levels of
branching per controller. No more than 127 devices, including the bus devices, may be connected to a single host
controller.
In USB terminology, devices (and hubs) are referred to as functions. These functions have associated pipes (logical
channels) which are connections from the host controller to a logical entity on the device endpoint. The pipes are
synonymous to byte streams. These endpoints (and their respective pipes) are numbered 0 to 15 in each direction, so a
function can have up to 32 active pipes, 16 inward and 16 outward. (The OUT direction should be interpreted out of the
host controller and the IN direction is into the host controller.) Each endpoint can transfer data in one direction only,
either into or out of the device/function. Each pipe is uni-directional. Endpoint 0 is however reserved for the bus
management in both directions and thus takes up two of the 32 endpoints. In these pipes, data is transferred in packets
of varying length. Each pipe has a maximum packet length so a USB packet will often contain something on the order
of 8, 16, 32, 64, 128, 256, 512 or 1 024 bytes.
5.2.2 Power Supply
The USB specification provides a 5 V supply and return from which connected USB devices may draw power. Initially
a device is only allowed to draw 100 mA. It may request more current from the upstream device in units of 100 mA up
to a maximum of 500 mA.
5.2.2.1 Versions and Data Rates
5.2.2.1.1 USB 1.0/1.1
Following are the specifications for are the specifications USB 1.0/1.1:
• 1,5 Mbps data transmission rate for 1.0.
• 12 Mbps data transmission rate for 1.1.
• Support for up to 127 devices.
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13 ETSI TR 102 021-9 V1.1.1 (2009-04)
• Hot Plug and Play capability.
• Both isochronous and asynchronous data transfers.
• Cable length of up to 5 meters.
• Built-in power supply/distribution for low-power devices.
5.2.2.1.2 USB 2.0
Key specifications for are the specifications USB 1.0/1.1:
• Contains all of the features of USB 1.0 and 1.1.
• Fully backward compatible with USB 1.0 and 1.1.
• Available in two versions: USB and Hi-Speed USB.
• Transmission speed of 12-Mbps for USB and 480 Mbps for Hi-Speed USB.
• All peripherals run at their highest rated speed instead of the speed of the slowest peripheral.
• Tested at a higher level than USB 1.0/1.1 so that it is more reliable.
NOTE: We have not found any information or experiment on USB data rates as a function of distance.
5.2.3 USB Backward Compatibility
Adopting the new technology and migrating towards USB physical link, is convenient for TETRA devices. Existing
terminals are implemented based on the EIA Recommended Standards such as EIA-232. For the purpose of backward
compatibility, it is possible to build a virtual COM port to move from a real Universal Asynchronous
Receiver-Transmitter (UART) system to a UART-USB system. There is also a wide range of converter cables available
in the market.
5.3 USB on the Go
USB On-The-Go [i.8] (normally abbreviated USB OTG) is a supplement to the USB 2.0 specification that allows USB
devices to transfer data directly between themselves.
5.3.1 Why USB OTG
Standard USB uses client/server architecture: one device acts as a USB host and the other as a USB peripheral. Only the
USB host contains the device driver and the necessary controls to transfer the data. The USB peripherals do not contain
those parts, so two USB peripherals cannot exchange the data without the use of USB hosts.
USB On-The-Go was developed to overcome that shortfall. With USB On-The-Go, the USB devices are given limited
ability to transfer data between themselves. If both are USB OTG, the connecting cable determines which one will
initially act as host, and the devices can negotiate to swap roles if needed. USB OTG devices can also connect to plain
USB devices from a target peripheral list.
USB OTG introduces one new port receptacle called AB connector. It can accept either an A plug or a B plug.
The OTG Supplement addresses the need for mobile interconnectivity by allowing a USB peripheral to have the
following enhancements:
• Host capability to communicate with selected other USB peripherals.
• A
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