Motorola T2290, T2297 Service Manual
Service Manual
DIGITAL WIRELESS TELEPHONE
Level 3
Release 1
™
TDMA T2290/T2297
COMPUTER SOFTWARE COPYRIGHTS
The Motorola products described in this instruction manual may include copy-righted Motorola computer programs stored in semi-conductor memories or othermedia. Laws in the United States and other countries preserve for Motorola certain exclusive rights for copyrighted computer programs, including the exclusive right to copy or reproduce in
any form the copyrighted computer program. Accordingly, any copyrighted Motorola computer programs contained in the Motorola products described in this instruction manual may not be copied or reproduced in any mannerwithout the express written permission of Motorola.
Furthermore, the purchase of Motorola products shall not be deemed to
grant either directly or by implication, estoppel, or otherwise, any license under the copyrights, patents or patent applica-tions of Motorola,
except for the normal non-exclusive, royalty free license to use that
arises by operation of law in the sale of a product.
This manual is the property of Motorola. No part of this
manual may be duplicated in any form without the express written permission of Motorola. This manual must
be returned upon Motorola request
The information in this manual is subject to change without notice. No
guarantee is made for accuracy or thoroughness. This manual is intended as a training aid in conjuction with formal classes provided by
Motorola. Motorola takes no responsibility for the use of this manual
beyond its intended scope.
Motorola, the Motorola Logo and all other trademarks identified as such herein are trademarks of Motorola, Inc. All
other product or service names are the property of their
respective owners.
© Copyright 2000 by Motorola, Inc. All rights reserved
Scope of Manual
This manual is intended for use by experienced technicians familiar with similar types
of equipment. It is intended primarily to support basic servicing, which consists primarily of mechanical repairs and circuit board
replacement.
Authorized distributors may opt to receive
additional training to become authorized to
perform limited component repairs. Contact
your regional Customer Support Manager for
details.
Model and Kit Identification
Motorola products are specifically identified
by an overall model number on the FCC label. In most cases, assemblies and kits which
make up the equipment also have kit model
numbers stamped on them.
Service
Motorola regional Cellular Subscriber Support Centers offer some of the Þnest repair
capabilities available to Motorola Subscriber
equipment users. The Cellular Subscriber
Support Centers are able to perform computerized adjustments and repair most defective
transceivers and boards. Contact your regional Customer Support Manager for more
information about MotorolaÕs repair capabilities and policy for in-warranty and outof-warranty repairs in your region.
About This Manual
General Safety Information
Portable Operation
DO NOT hold the radio so that the antenna
is very close to, or touching, exposed parts of
the body, especially the face or eyes, while
transmitting. The radio will perform best if
it is held in the same manner as you would
hold a telephone handset, with the antenna
angled up and over your shoulder. Speak directly into the mouthpiece.
DO NOT operate the telephone in an airplane.
DO NOT allow children to play with any
radio equipment containing a transmitter.
Mobile Operation (Vehicle Adaptor)
As with other mobile radio transmitting
equipment, users are advised that for satisfactory operation of the equipment and for
the safety of personnel, it is recommended
that no part of the human body shall be allowed to come within 20 centimeters of the
antenna during operation of the equipment.
DO NOT operate this equipment near electrical blasting caps or in an explosive atmosphere. Mobile telephones are under certain
conditions capable of interfering with blasting operations. When in the vicinity of construction work, look for and observe signs
cautioning against mobile radio transmission. If transmission is prohibited, the cellu-
©2000 Motorola, Inc.
iii
lar telephone must be turned off to prevent any transmission. In standby mode, the
mobile telephone will automatically transmit
to acknowledge a call if it is not turned off.
All equipment must be properly grounded
according to installation instructions for safe
operation.
Portable/Mobile Telephone Use and
Driving
Safety is every driver’s business. The portable
telephone should only be used in situations
in which the driver considers it safe to do so.
Use of a cellular portable while driving may
be illegal in some areas.
Refer to the appropriate section of the product service manual for additional pertinent
safety information.
TDMA T2290/T2297About This Manual
iv
©2000 Motorola, Inc.
Specifications
Table 1.Overall System
Function Specification
Frequency Range
TX (800MHz)
RX(800 MHz): 869.04 – 893.97 MHz
TX (1.9 GHz) : 1850.01 – 1909.95 MHz
: 824.04 - 848.97 MHz
Channels 1 to 799, fTX = 0.03 * N+ 825MHz
Channels 990 to 1023, fTX = 0.03(N-1023)+ 825MHz
Channels 1 to 799, fRX = 0.03 * N+ 870MHz
Channels 990 to 1023, fRX = 0.03(N-1023)+ 870MHz
Channels 1 to 1999 fTX = 0.03 * N+ 1849.98MHz
About This ManualService Manual
RX (1.9 GHz)
Channel Spacing 30 kHz
Channels 832 (800MHz), 1999 (1.9 GHz)
Duplex Spacing 45 MHz (800MHz), 80.04 MHz (1.9GHz)
Input/Output Impedance 50 ohms (nominal)
Operating Voltage +3.6 to +4.1Vdc
Dimensions 120cc (Volume)
Weight 140 g
Display 96 X 32 Graphic Matrix
Analog RF Power Output 0.316 Watts (25 dBm)
Digital RF Power Output 0.562 Watts (27.5 dBm)
Automatic Power Control 9, 4 dBm steps
: 1930.05 – 1989.99 MHz
Channels 1 to 1999 fRX = TX + 80.04MHz
Table 2. EAMPS System
Function Specification
Modulation Type FM
Frequency Stability + 2.5ppm
Duty Cycle Continuous
Audio Distortion
(transmit and receive)
FM Hum and Noise
(C-MSG weighted)
Voice Modulation Maximum + 12 kHz deviation
Transmit Audio Sensitivity 9 kHz deviation (nom.) @ 97 dB SPL input @ 1 kHz
Receive Sensitivity -116 dBm for 12 dB SINAD (C-MSG weighted)
Adjacent and Alternate
Channel Desensitization
IM Greater than 65 dB
Less than 5% at 1 kHz; + 8 kHz deviation
32 dB below + 8 kHz deviation @ 1 kHz
-16 dB @ +30 kHz, -60 dB @ + 60 kHz
©2000 Motorola, Inc.
v
Table 3. DAMPS System
Function Specification
Modulation Type
Frequency Stability + 200 Hz
Duty Cycle 32.3%
Error Vector Magnitude
(π/4DQPSK mode)
Transmit Audio Sensitivity TOLR of –46 dB nominal
Receive Sensitivity -116 dBm for 3% static BER
Adjacent and Alternate
Channel Desensitization
IM Less than or equal to 3% static BER
π/4DQPSK
Error Vector Magnitude [Digital] 12.5%
-116 dBm for 3% static BER
Table 4. Environment
TDMA T2290/T2297About This Manual
Function Specification
Temperature -30ºC to +60ºC
Humidity 80% RH at 50ºC
Vibration EIA PN1376
Shock EIA PN1376
vi
©2000 Motorola, Inc.
Table of Contents
About This Manual ....................................................................................................................... iii
Scope of Manual ....................................................................................................................... iii
Model and Kit Identification....................................................................................................... iii
Service...................................................................................................................................... iii
General Safety Information ....................................................................................................... iii
Portable Operation........................................................................................................................................ iii
Mobile Operation (Vehicle Adaptor) ............................................................................................................... iii
Portable/Mobile Telephone Use and Driving...................................................................................................iv
Specifications.............................................................................................................................v
Cellular Overview .......................................................................................................................... 1
Introduction ................................................................................................................................1
Control (Data) Channels ................................................................................................................................2
Voice Channels.............................................................................................................................................. 3
Signaling Protocol ..........................................................................................................................................3
Analog Cellular...........................................................................................................................5
Signaling Tone (ST) and Digital ST (DST).......................................................................................................5
SAT (Supervisory Audio Tone) and DSAT (Digital SAT) ...................................................................................6
DTMF (Dual Tone Multi-Frequency)................................................................................................................ 6
Analog Cellular Signal Summary (AMPS and NAMPS) ...................................................................................7
Going into Service .........................................................................................................................................8
Placing a Call (Mobile to Land or Mobile to Mobile) .......................................................................................10
Receiving a Call (Land to Mobile) .................................................................................................................11
Power Steps ................................................................................................................................................13
Hand-offs.....................................................................................................................................................13
Call Termination ...........................................................................................................................................15
Digital Cellular..........................................................................................................................17
Multiplexing .................................................................................................................................................17
FDMA (Frequency Division Multiple Access).................................................................................................17
Digitizing Voice ............................................................................................................................................17
TDMA (Time Division Multiple Access) .........................................................................................................18
Digitization and TDMA .................................................................................................................................18
Digitization of Voltage...................................................................................................................................19
Conventional Radio......................................................................................................................................19
TDMA Radio ................................................................................................................................................20
Accessories ................................................................................................................................. 21
TDMA EASY NAM Programming................................................................................................ 23
Introduction ..............................................................................................................................23
User Mode Programming.........................................................................................................23
Programming Sequence ..........................................................................................................24
©2000 Motorola, Inc.
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TDMA T2290/T2297Table of Contents
Enter Programming Mode ............................................................................................................................24
Enter Security Code.....................................................................................................................................24
Enter Phone Number ...................................................................................................................................24
Programming a second No...........................................................................................................................24
If you make a mistake ..................................................................................................................................24
TDMA Test Mode NAM Programming ........................................................................................ 25
Introduction ..............................................................................................................................25
Entering Test Mode NAM Programming...................................................................................25
NAM Programming Steps ........................................................................................................25
NAM Data ................................................................................................................................26
User Mode Programming.........................................................................................................26
Test Mode NAM Programming Sequence................................................................................27
Manual Test Mode........................................................................................................................ 31
Introduction ..............................................................................................................................31
Entering Manual Test Mode .....................................................................................................31
Status Display Level ................................................................................................................31
Servicing Level.........................................................................................................................32
Test Procedures .......................................................................................................................... 35
Introduction ..............................................................................................................................35
Automatic Call-Processing Tests..............................................................................................35
Analog Test Measurements ..........................................................................................................................35
Digital Test Measurements ...........................................................................................................................35
Test Connections .....................................................................................................................36
RF Cable Test ..........................................................................................................................37
To test the RF cable for proper loss: .............................................................................................................37
Set up for Analog call ...............................................................................................................38
Registration .................................................................................................................................................38
Page............................................................................................................................................................38
Select CALL CNTL from the To Screen.........................................................................................................38
Origination ...................................................................................................................................................38
RX Sensitivity Test (SINAD) .....................................................................................................39
Test Mode Commands: ................................................................................................................................39
Communications Analyzer Setup:.................................................................................................................39
TX Power Out Test...................................................................................................................40
Test Mode Commands: ................................................................................................................................40
Communications Analyzer Setup:.................................................................................................................40
Test Mode Commands: ................................................................................................................................41
Communications Analyzer Setup:.................................................................................................................41
TX Maximum Deviation Test ....................................................................................................42
Test Mode Commands: ................................................................................................................................42
Communications Analyzer Setup:.................................................................................................................42
TX SAT Deviation Test .............................................................................................................43
Procedure....................................................................................................................................................43
Select CALL CNTL from the To Screen.........................................................................................................43
TX ST Deviation Test ...............................................................................................................44
Test Mode Commands: ................................................................................................................................44
viii
©2000 Motorola, Inc.
Table of ContentsService Manual
Communications Analyzer Setup:.................................................................................................................44
Setting up for PCS TDMA Measurements................................................................................45
Power up the PCS Adapter, after two beeps are heard power up the 8920B.................................................45
Setting up for PCS TDMA Measurements................................................................................46
Set up for TDMA call ................................................................................................................47
Call Process ................................................................................................................................................47
Registration .................................................................................................................................................47
Select CALL CNTL from the To Screen.........................................................................................................47
Page............................................................................................................................................................47
Origination ...................................................................................................................................................47
MAHO Measurements .............................................................................................................48
Setting up the MAHO measurement .............................................................................................................48
Measuring MAHO ........................................................................................................................................48
BER Measurements.................................................................................................................49
PCS Mode Handset Commands:..................................................................................................................49
BER Measurement Procedure......................................................................................................................49
TX Power Measurements ........................................................................................................50
PCS Mode Handset Commands:..................................................................................................................50
Digital TX Power Out Test Procedure ...........................................................................................................50
TX Frequency Error Measurements.........................................................................................51
PCS Mode Handset Commands:..................................................................................................................51
TX Frequency Error Measurement Test ........................................................................................................51
EVM Measurements ...............................................................................................................52
PCS Mode Handset Commands:..................................................................................................................52
TX Frequency Error Measurement Test ........................................................................................................52
Disassembly ................................................................................................................................ 53
Introduction ..............................................................................................................................53
Recommended Tools ...............................................................................................................53
Battery Removal ......................................................................................................................54
Antenna Removal ....................................................................................................................55
Back Housing Removal............................................................................................................55
Transceiver Board Removal.....................................................................................................56
Display Removal ......................................................................................................................56
Keypad Removal......................................................................................................................57
Speaker Removal ....................................................................................................................57
Parts List ...................................................................................................................................... 59
Introduction ..............................................................................................................................59
Mechanical Explosion ..............................................................................................................59
General Description .................................................................................................................... 61
Antenna Circuit ........................................................................................................................61
RX Front End ...........................................................................................................................61
NADC IC ..................................................................................................................................61
TX Operational Description.....................................................................................................62
Power Amp Integrated 800 MHz or 1900 MHz IC ....................................................................62
Analog TX Audio Processing ...................................................................................................63
©2000 Motorola, Inc.
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TDMA T2290/T2297Table of Contents
Digital TX Audio Processing.....................................................................................................63
DSP Lucent 1629.....................................................................................................................63
Stuart IC...................................................................................................................................64
GCAP II....................................................................................................................................64
Section B
Service Diagrams ....................................................................................................................... B1
Antenna Circuit ....................................................................................................................... B3
Front End IC(U10)................................................................................................................... B5
ZIFSYNTH(U110).................................................................................................................... B7
VCO ........................................................................................................................................ B9
TX Offset Oscillator............................................................................................................... B11
Merlyn(U301) ........................................................................................................................ B13
Exciter................................................................................................................................... B15
PA Circuit .............................................................................................................................. B17
RF Detect.............................................................................................................................. B19
Reference Oscillator ............................................................................................................. B21
DCI(U1800)........................................................................................................................... B23
GCAP2(U1500)..................................................................................................................... B25
Voltage Regulators................................................................................................................ B27
Charger................................................................................................................................. B29
Audio Circuit.......................................................................................................................... B31
DSP(U1900).......................................................................................................................... B33
STUART(U1907)................................................................................................................... B35
Call Processor(U1000).......................................................................................................... B37
Memory ................................................................................................................................. B39
B+ Disconnect/Backlight Driver............................................................................................. B41
Keypad.................................................................................................................................. B43
Connectors............................................................................................................................ B44
Layout Side 1........................................................................................................................ B45
Layout Side 2........................................................................................................................ B46
x
©2000 Motorola, Inc.
Cellular Overview
Introduction
A cellular mobile telephone system divides
the service area into small, low power radio
frequency coverage areas called cells. A cellular system consists of a more or less continuous pattern of these cells, each having a
1 to 40 mile radius (typically 5 - 10 miles).
Within each cell is a centralized cell site with
an elevated antenna and a building. The
building houses a base station with transceivers and related control equipment for the
Figure 1. Channel Assignments
A BAND CHANNELS
Primary Control Channels (21): 313 - 333
Secondary Control Channels (21): 688 - 708
Voice Channels... 001 - 312,
(395 AMPS / 1185 NAMPS): 667 - 716, and
channels assigned to that cell. All the cell
sites within a system are then connected either by dedicated land lines, microwave links,
or a combination of both to a central control
site called the central controller or switch .
The switch controls the entire cellular system and serves as the interface between the
cellular telephone user and the landline network. Each cell site operates on an assigned
access channel, and may have any number
of paging and voice channels assigned to it.
991 - 1023
B BAND CHANNELS
Primary Control Channels (21): 334 - 354
Secondary Control Channels (21): 737 - 757
Voice Channels... 355 - 666 and
(395 AMPS / 1185 NAMPS): 717 - 799
NOTE:
In NAMPS applications, each AMPS voice channel
provides space for three NAMPS voice channels.
Digital cellular multiplexes voice channels to allow for the
possibility of several additional conversations on a single channel.
©2000 Motorola, Inc.
1
US Cellular Frequency Band
Introduction
The cellular radio frequency spectrum has
been divided by the FCC into two equal segments or bands to allow two independent cellular carriers to coexist and compete in the
same geographic coverage area. Each band
occupies one half of the available channels
in the cellular spectrum. Initially there were
666 channels available across the entire cellular spectrum, but that number was expanded to 832 channels in 1987, and with
NAMPS to 2,412 channels in 1991. Digital
cellular promises to make a further expansion. To guarantee nationwide compatibility, the signaling channel frequencies have
been pre-assigned to each segment (band).
The two bands and their assigned channels
TDMA T2290/T2297Cellular Overview
are defined in Figure 1.
Originally the B Band was assigned to the
telephone company (referred to by a euphemism, the Wireline carrier). The A Band, by
default, was referred to as the Non-Wireline
carrier, guaranteed competition to the telephone company. Today the terms Wireline
and Non-Wireline have little meaning since
telephone company carriers now operate A
Band systems, and vice-versa.
Control (Data) Channels
A cellular telephone in the cellular system is
under the indirect control of the switch, or
central controller. The central controller uses
dedicated control channels to provide the sig-
Figure 2. US Cellular Frequency Band
832 channels
333
334
1023
991 666
001
A' A' B'
A A
Band A Band B
Voice
Channels
313
312
Channels
Control
354
355
BB
Voice
Channels
666
667
716
667
717
716
A'
717
799
799
2
TDMA Secondary
Control Channels
©2000 Motorola, Inc.
737 - 757688 - 708
Cellular OverviewService Manual
Introduction
naling required to establish a telephone call.
Control channels are used to send and receive
only digital data between the base station
and the cellular telephone. Voice channels
are used for both audio and signaling once a
call is established. The 21 control channels
in each band may be dedicated according to
two different applications: access and paging channels.
The data on the forward control channel generally provides some basic information about
the particular cellular system, such as the
system ID and the range of channels to scan
to find the access and paging channels. Access channels are used to respond to a page
or originate a call. The system and the cellular telephone will use access channels
where two-way data transfer occurs to determine the initial voice channel. Paging channels, if used, are the normal holding place
for the idle cellular telephone. When a call
is received at the central controller for a cellular telephone, the paging signaling will
occur on a paging channel. In many systems
both control channel functions will be served
by the same control (access) channel for a particular cell. Only in very high density areas
will multiple control (paging) channels be required.
Primary control channels are used by all
types of telephones. Secondary control channels are only used by TDMA telephones, providing them with an improved probability of
locking onto a TDMA control channel.
Voice Channels
Voice channels are primarily used for conversation, with signaling being employed as
necessary to handle cell-to-cell hand-offs,
output power control of the cellular radiotelephone, and special local control features.
Data from the cell site (known as FORWARD
DATA) and data from the mobile or portable
(known as REVERSE DATA) is sent using
frequency shift keying. In AMPS signaling,
various control and response tones are used
for a variety of applications to be described
later. However, in NAMPS signaling, the signaling data and tones have been replaced by
sub-audible digital equivalents that constantly ride underneath the audio. And, of
course, in digital cellular, all signaling is digital.
Signaling Protocol
In 1983, when the Federal Communications
Commission (the FCC) licensed cellular telephony, the signaling protocol used was
AMPS. AMPS (Advanced Mobile Phone Service) was the invention of Bell Labs, the signaling protocol that was ultimately adopted
by all the governments of the entire Western
Hemisphere and, eventually, several other
governments throughout the world.
Today, with the implementation of Narrow
AMPS and TDMA, and the imminence of
CDMA, it may seem that AMPS is out of date.
The truth is that AMPS is very much alive,
at the very core of all these traffic expanding
alternatives to the original signaling protocol developed for conventional cellular telephony.
Under the original AMPS protocol there were
21 control channels assigned to each of two
possible carriers in any metropolitan area,
with a total of 333 channels assigned to each
carrier. Prior to 1987 the FCC had allocated
312 channels to voice (voice, DTMF, or data)
©2000 Motorola, Inc.
3
Introduction
TDMA T2290/T2297Cellular Overview
applications for each carrier. In 1987 the
FCC expanded the cellular spectrum (Expanded Spectrum) from a total of 666 channels to 832 channels, allowing for an increase
of 83 voice channels for each carrier. But the
number of control channels remained constant, 21 control channels for each carrier.
In 1991, responding to the demand for even
more voice channels, Motorola introduced
NAMPS (Narrow AMPS), expanding the
voice channels by a factor of 3, assuming all
subscribers are using NAMPS telephones.
But one thing remained constant, there were
21 control channels for each carrier.
In 1992, when Motorola tested its TDMA digital product, digitizing three communication
links on each of 395 voice channels, one thing
remained constant: there were still 21 con-
trol channels for each carrier.
between digital cellular and AMPS is that
all signals are digitized, including voice.
At a basic level, cellular telephony has two
divisions: analog cellular and digital cellular. In the following section, analog cellular
(AMPS and NAMPS) will be discussed. In
the succeeding section, digital cellular will
be treated.
Leaving the control channels more or less untouched is the key to allowing telephones that
are not capable of NAMPS or digital operation to have access to the system using the
conventional AMPS scheme. In virtually
every scheme (AMPS, NAMPS, or digital),
each control channel has a bandwidth of 30
kHz and uses the signaling protocol, with
minor variations for NAMPS and digital,
developed for conventional AMPS
The primary difference between NAMPS and
AMPS is that a NAMPS voice channel has a
bandwidth of only 10 kHz, whereas an AMPS
voice channel has a bandwidth of 30 kHz. In
addition, NAMPS does not make use of certain control and response tones on voice channels as does AMPS, but uses digital equivalents instead.
As the name implies, the primary difference
4
©2000 Motorola, Inc.
Cellular OverviewService Manual
Analog Cellular
Analog Cellular
The simplified block diagram on page 1 - 7
illustrates an imaginary layout of one side
(Band A, or Band B) of a hypothetical service
area. The hexagons represent cells, and some
of the cell sites shown here also illustrate the
fact that an antenna tower and set of base
stations are associated with each site. In a
real world environment individual cells do
not have the hexagonal shape but may take
any form as dictated by the environment.
The cell sites are in communication with individual portable and mobile cellular telephones. These portables and mobiles may
move from cell to cell, and as they do they
are “handed off” under the supervision of the
Figure 3. Channel Assignments
central controller (switch).
As illustrated(figure 3.) by the antenna tower
on the upper left, cell sites transmit overhead
messages more or less continuously even if
there are no mobiles or portables active
within that cell.
The switch (center left) is in control of the
system and interfaces with the central office
of the telephone company. As illustrated by
the deskset telephones, the telephone company interfaces with the entire landline network.
The cell sites and the mobiles and portables
communicate through the use of data or, in
the case of AMPS, through the use of data
and tones. A complete analysis of data signaling is beyond the scope of this manual.
Refer to the Electronic Industries Association
standard EIA-553 for a thorough discussion
of AMPS signaling protocol, or to Motorola’s
NAMPS Air Interface Specification for
NAMPS.
Cellular
Switch
Telephone
Company
Central Office
The tones used in AMPS signaling are Signaling Tones and Supervisory Audio Tones.
NAMPS uses sub-audible digital equivalents.
Signaling Tone (ST) and Digital ST (DST)
In AMPS, signaling tone is a 10 kHz signal
used by the mobile or portable on the reverse
voice channel (REVC) to signal certain activities or acknowledge various commands
from the cell site, including hand-offs, alert
orders, and call terminations, and to indicate
switch-hook operation. Various burst lengths
are used for different ST activities. On
NAMPS channels ST is replaced by a digital
equivalent called Digital ST (DST) which is
©2000 Motorola, Inc.
5
Analog Cellular
TDMA T2290/T2297Cellular Overview
the complement of the assigned DSAT.
SAT (Supervisory Audio Tone) and DSAT
(Digital SAT)
The Supervisory Audio Tone (SAT) is one of
three frequencies around 6 kHz used in
AMPS signaling. On NAMPS channels SAT
is replaced by one of seven sub-audible digital equivalents or vectors called DSAT. SAT
(or DSAT) is generated by the cell site,
checked for frequency or accuracy by the cellular telephone, then transponded (that is,
not merely reflected but generated and returned) to the cell site on the reverse voice
channel (REVC). The cellular telephone uses
(D)SAT to verify that it is tuned to the correct channel after a new voice channel assignment. When the central controller
(switch) signals the mobile regarding the new
Figure 4. Channel Assignments
voice channel, it also informs the mobile of
the SAT frequency or DSAT vector to expect
on the new channel. The returned (D)SAT
is used at the cell site to verify the presence
of the telephone’s signal on the designated
channel.
In general there are three uses of (D)SAT:
(a) it provides a form of squelch; (b) it provides for call continuation (but if equipped
for it, the switch will allow for VOX on all
models); and (c) (D)SAT is used to prevent
co-channel interference.
DTMF (Dual Tone Multi-Frequency)
DTMF (Dual Tone Multi-Frequency) touchcode dialing may also occur on voice channels. DTMF selects two tones from a total of
nine (cellular only uses seven of these tones /
four low and three high tones) to uniquely
represent individual keys.
SAT 0 (5970 Hz)
SAT 1 (6000 Hz)
SAT 2 (6030 Hz)
Re-use
Cellular System
327
329
333
324
332
328
326
330
140
119
98
77
56
326
313
198
177
156
135
114
331
318
324
143
122
101
80
320
322
326
319
330
140
119
98
77
56
Table 5. DTMF Values
Key Low Tone High Tone
1 697 1209
2 697 1336
3 697 1477
4 770 1209
5 770 1336
6 770 1477
7 852 1209
8 852 1336
9 852 1477
* 941 1209
0 941 1336
# 941 1477
6
©2000 Motorola, Inc.
Cellular OverviewService Manual
AMPS Deviation in kHz
Analog Cellular
Analog Cellular Signal Summary (AMPS
and NAMPS)
The diagrams on the following pages outline the various uses of the signals employed
in cellular systems. These signals include:
SAT (Supervisory Audio Tone) 5970 Hz, 6000
Hz, or 6030 Hz. Used in AMPS for channel reuse, muting audio (squelch), and call
continuation [typically ± 2 kHz deviation].
Digital SAT (DSAT) - One of seven codes or
vectors used in NAMPS for the same purpose as SAT [± 700 Hz sub-audible NRZ
data].
Data - Transmitted at 10 kilobits/second in
AMPS and 200 bits/second in NAMPS. Data
is used for sending System Orders and Mobile Identification. Do not confuse data with
the 10 kHz signaling tone. In AMPS, data is
transmitted as Manchester-encoded Frequency Shift Keying (FSK), where the carrier is shifted high or low 8 kHz, and the trailing edge transition is used to represent the
logic. In NAMPS, data is transmitted as NRZ
(Non-Return to Zero) FSK, where the carrier
is shifted high or low 700 Hz, and the frequency shift itself is used to represent the
logic.
Signaling Tone (ST) - A 10 kHz tone used in
AMPS for mobile ringing, call terminations,
hand-offs, and switch-hook operation [typically ± 8 kHz deviation]. ST is always accompanied by SAT.
Digital ST (DST) - One of seven digital
equivalents of ST used on NAMPS channels.
The transmitted DST is always the complement of the assigned DSAT [± 700 Hz subaudible NRZ data].
Audio - Includes microphone audio and
DTMF [maximum ± 12 kHz deviation AMPS,
± 5 kHz deviation NAMPS]. DTMF deviation should be measured on the radians scale;
use key five looking for 9 radians. Audio is
accompanied by SAT in AMPS signaling.
Figure 5. AMPS Deviation in kHz
AMPS Voice Channels
±14
±12
±10
± 8
± 6
± 4
± 2
Data
SAT
SAT
SAT
Signal
Audio
Tone
©2000 Motorola, Inc.
Control
Channels
DataDataAudio
7
Analog Cellular
Total deviation of two or more signals is cumulative.
Going into Service
When first turned on, the cellular telephone
will scan through the nationwide set of forward control channels (FOCC’s) and measure
the signal strength on each one. It will then
tune to the strongest one and attempt to decode the overhead control message. From the
overhead message, the telephone will be able
to determine whether or not it is in its home
system, and the range of channels to scan for
paging and access. Telephones not in their
home system will be able to use other cellular telephone systems depending on the level
of service requested by the user. If paging
channels are used, the telephone next scans
each paging channel in the specified range
and tunes to the strongest one. On that channel the telephone continuously receives the
overhead message information plus paging
messages. At this point the telephone idles,
continuously updating the overhead message
information in its memory and monitoring
the paging messages for its telephone number.
TDMA T2290/T2297Cellular Overview
Step 5. Decision point. Can the overhead
message from the strongest control
channel be decoded? If not, go to
step 6. If it can be decoded go to
step 8.*
Step 6. The telephone tunes to the second
strongest channel.
Step 7. Decision point. Can the overhead
message stream be decoded? If not,
go to step 12. If it can be decoded,
go to step 8.*
Step 8. Decision point. Does the decoded
System ID match the Home System ID programmed in the telephone? If not, go to step 9. If it
does match, go to step 10.
Step 9. The telephone turns on the ROAM
indicator.
Step 10. The telephone turns off the NoSvc
indicator.
Step 11. The telephone idles. Typically a re-
scan occurs after 5 minutes.
Step 1. The telephone powers up and runs
a self-test. The NoSvc indicator is
illuminated.
Step 2. The telephone scans its preferred
system (A or B) as selected in programming.
Step 3. The telephone scans all twenty-one
control channels.
Step 4. The telephone tunes to the stron-
gest control channel.
8
©2000 Motorola, Inc.
Step 12. The telephone turns on (or leaves
on) its NoSvc indicator.
Step 13. The telephone switches to the non-
preferred system as recorded in
programming, and goes back to
step 3. The ability to return to step
3 can be disabled by some settings
of System Registration.
*The area between Decision point 5 and Decision point 8 can be quite active.
In a few larger systems, following the suc-
Cellular OverviewService Manual
Going Into Service
Analog Cellular
cessful completion of either steps 5 or 7, the
telephone scans a set of paging channels,
tunes to the strongest, and attempts to decode the overhead message train. The procedure is exactly equivalent to that followed
for the access (control) channel. Also at this
point, in a few larger systems, the telephone
is commanded to identity itself (transmit) and
thereby indicate its location in the system.
This is called Autonomous System Registration and, like paging channels, is used to improve paging efficiency.
Figure 6. Going into Serivce
1. Power Up / Self Test
Turn on No Svc Indicator
If the system employs Narrow AMPS, part
of the overhead message stream is used to
ask the for activity on one of the secondary
or “digital” control channels, whereas a
CDMA telephone will look for pilot signals.
If digital signaling is not present, and if the
telephone is capable of dual mode operation,
it will default to AMPS mode.
With a Cellular Telephone
2. Scan Preferred
System (A or B)
3. Scan all 21
Control Channels
4. Tune to Strongest
Control Channel
5.
Receive
Overhead
Info
?
Yes
8.
SID matches
Home SID
?
Note: In order to turn off
the NoSvc light, the
overhead message stream
must have been decoded.
* In those telephones with Motorola Enhanced Scan, more than two control channels are sampled
before proceeding to step 12.
Yes
No
No
6. Tune to 2nd
Strongest Channel
Note: In order to turn on the
Roam light, the SID in the
overhead message stream must
NOT match the SID
programmed into the telephone.
9. Turn on
Roam Indicator
10. Turn Off
NoSvc Indicator
11. Idle [Rescan
after 5 minutes.]
7.
Receive
Overhead
Info
?
Yes
No*
12. Turn On
NoSvc Indicator
13. Switch to
Non-Preferred System
©2000 Motorola, Inc.
9
Analog Cellular
TDMA T2290/T2297Cellular Overview
Placing a Call (Mobile to Land or Mobile to
Mobile)
When the cellular telephone user originates
the call, the cellular telephone re-scans
the access channels to assure that it is still
tuned to the strongest one. The cellular tele-
Figure 7. Cellular Telephone to Land Call Processing
Cellular Telephone Landline NetworkSwitch / Cell Site
The cellular telephone is
tuned to the access / paging
channel, and responds to
requests for data.
The cellular telephone user
dials a telephone number
and presses SND. The tele-
phone rescans the access
channels for the strongest
signal. The telephone
sends out data, including
the dialed digits, MIN, ESN,
and NAMPS or digital
capability to the cell site.
The cellular telephone
receives the voice channel
assignment, drops the
access channel, tunes to the
voice channel, and
transponds the assigned
SAT or DSAT.
DATA
FOCC
&
RECC
DATA
RECC
DATA
FOCC
(D)SAT
FOVC
(D)SAT
REVC
Overhead data is sent out
on the control channels.
The cell site receives the
mobile-to-land call request.
The cell site sends the data to
the switch. The switch
verifies the MIN & ESN and
then sends out the call to the
landline network.
The switch assigns a voice
channel and SAT or DSAT.
The voice channel assignment is sent to the cellular
telephone on the access
channel. The cell site sends
SAT or DSAT to the cellular
telephone on the assigned
voice channel.
The cell site receives the
correct SAT or DSAT, then
unmutes the voice path.
phone then transmits data at the rate of 10
kilobits per second on the control channel to
notify the switch of its mobile identification
number (MIN) and the number it wants to
reach. The switch verifies the incoming data
and assigns a voice channel and a SAT (or
DSAT for NAMPS channels) to the telephone.
The local telephone
company processes the
telephone call.
10
The cellular telephone user
hears the landline ringing.
Conversation in progress
VOICE + (D)SAT
FOVC & REVC
©2000 Motorola, Inc.
The landline person being
called answers.
Conversation in progress
Cellular OverviewService Manual
Analog Cellular
The cellular telephone tunes to the assigned
voice channel and verifies the presence of the
proper forward SAT frequency (or DSAT message). If SAT (DSAT) is correct the telephone
transponds SAT (DSAT) back to the cell site
and unmutes the forward audio. The cell site
detects reverse SAT (DSAT) from the cellular telephone and unmutes reverse audio. At
this point both forward and reverse audio
paths are unmuted and the cellular telephone
user can hear the other end ring, after which
conversation can take place. SAT (DSAT) is
sent and received more or less continuously
by both the base station and the cellular telephone. However, SAT (DSAT) is not sent during data transmissions, and the cellular telephone does not transpond SAT continuously
during VOX operation. Also, DSAT is suspended during the transmission of DST.
Notice that SAT and Signaling Tones are only
used on AMPS voice channels, and that the
Signaling Tone is only transmitted by the cellular telephone.
site, the reception of SAT (DSAT) signals the
central controller that the cellular telephone
is ready for the call. An alert order is then
sent to the cellular telephone which responds
with a 10 KHz signaling tone (DST message).
The subscriber unit rings for 65 seconds or
until the user answers. Then the 10 KHz
signaling tone (DST message) is terminated
to alert the central controller that the user
has answered. The switch then connects the
incoming call to the appropriate circuit leading to the cell in contact with the cellular telephone. At this point both forward and reverse audio paths are unmuted and the conversation can take place. SAT (DSAT) is sent
more or less continuously by the base station and transponded by the cellular telephone, except during data transmission.
DSAT is suspended during DST transmission, and during VOX operation SAT (DSAT)
is not transponded continuously by the cellular telephone.
Receiving a Call (Land to Mobile)
Once a cellular telephone has gone into service, it periodically scans the overhead message information in its memory and monitors the paging messages for its telephone
number. When a page match occurs the
cellular telephone scans each of the access
channels and tunes to the strongest one. The
cellular telephone then acknowledges the
page on that access channel and thus notifies the central controller of its cell location.
The switch then assigns a voice channel and
a SAT (DSAT) to the cellular telephone. The
cellular telephone tunes to the voice channel, verifies the presence of the proper SAT
frequency (DSAT message) and transponds
the signal back to the cell site. At the cell
©2000 Motorola, Inc.
11
Figure 8. Land to Cellular Telephone Call Processing
TDMA T2290/T2297Cellular Overview
Landline Network
The landline caller dials the
cellular telephone number.
The Public Service Telephone
Network (central office)
forwards the call to the central
controller (switch).
The landline caller hears
ringing, busy, etc.
Switch / Cell Site
Overhead data is sent out
on the control channels.
The switch receives a call from
land. The switch pages the
cellular telephone. The page is
sent as data on the forward
control channel.
The cell site receives the
acknowledgement and sends it
to the switch. The switch
verifies the ESN & MIN and
assigns a voice channel.
The cell site informs the
cellular telephone of the voice
channel and SAT (DSAT).
The cell site sends the SAT
(DSAT) on the voice channel.
The cell site receives the correct
SAT (DSAT) and alerts the
cellular telephone to ring.
The cell site receives signaling
tone (DST message) from the
cellular telephone.
DATA
FOCC
&
RECC
DATA
FOCC
DATA
RECC
DATA
FOCC
(D)SAT
FOVC
(D)SAT
REVC
DATA
FOVC
(D)ST +
(D)SAT
REVC
Cellular Telephone
The cellular telephone is
tuned to the
access / paging
channel, and responds
to requests for data.
The cellular Telephone
decodes the data and
successfully reads its MIN.
The telephone scans the
control channels for the
strongest, then acknow-
ledges the page by sending
it’s ESN, MIN, and NAMPS
or digital capability as data
on the control channel.
The telephone receives
the data and tunes to the
assigned voice channel,
then transponds
the SAT (DSAT).
The cellular telephone
rings. While ringing, the
subscriber unit sends a 10
kHz signaling tone (DST
message) to the cell site.
12
Conversation in progress
The cell site unmutes the
voice path.
VOICE + (D)SAT
FOVC & REVC
©2000 Motorola, Inc.
(D)SAT
REVC
The cellular telephone user
answers by pressing SND
The signaling tone stops.
Conversation in progress
Voice path unmuted
Cellular OverviewService Manual
Analog Cellular
Power Steps
As a call progresses, the cell site continuously
monitors the reverse channel for signal
strength.
Every cellular telephone has a number of
power steps ranging from full power (3 watts
in a mobile and .6 watts in a portable) down
to as low as about half a milliwatt. In reality all cellular telephones have eight power
steps, but portable models are prevented from
using the two highest power steps by the cell
site. Transmit power level commands are
sent to the cellular telephone as required to
maintain the received signal strength within
prescribed limits.
This is done to minimize interference possibilities within the frequency re-use scheme.
If the signal received from the cellular telephone is higher than the prescribed limit
(such as when the unit is very near the cell
site), the subscriber unit will be instructed
to step down to a lower level.
Hand-offs
If the cellular telephone is at its maximum
allowed power for the cell site it is using and
the received signal at the cell site is approaching the minimum allowable (typically -100
dBm), the cell site will signal the switch to
consider the subscriber unit for a hand-off.
The central controller (switch) will in turn
have a scanning receiver at each of the surrounding cell sites measure the cellular
telephone’s signal strength. The site with
the strongest signal will be the site to which
the call will be handed to if there are available voice channels.
On an AMPS channel the hand-off is executed
by interrupting the conversation with a burst
of data (called blank and burst) containing
the new voice channel assignment. The telephone acknowledges the order by a 50 millisecond burst of 10 kHz signaling tone on the
originally assigned voice channel. The mobile telephone then drops the original voice
channel and tunes to the newly assigned voice
channel, keying up on that channel and
transponding the assigned SAT. But on a
NAMPS channel the hand-off is executed
with a low speed data transmission that does
not interrupt the voice. The telephone acknowledges the order in this case by a DST
message. In either case, once the hand-off
has been accomplished, the newly assigned
cell site then alerts the switch that the handoff has been completed, and the old voice
channel is dropped.
It should be noted that this data exchange
happens very quickly, lasting only as long as
260 milliseconds. However, when data or
signaling tones are transmitted, audio is
muted for the duration of that transmission
and a syllable or two may be dropped from
conversation. This is normally not a problem, but during data signaling, such as that
employed for telefacsimile, answering machine, and computer communications, significant amounts of information may be lost. For
this reason it is recommended that when
THE Cellular Connection™ equipment is
used the vehicle should be stationary to avoid
data loss during hand-offs and other data
transmissions. Otherwise the equipment
should employ an error correction protocol.
©2000 Motorola, Inc.
13
Figure 9. Cell Site Handoffs
TDMA T2290/T2297Cellular Overview
Cellular Telephone Landline Network
Conversation in progress.
The voice path is unmuted.
The cellular telephone
acknowledges the handoff
request by sending a10 kHz
signaling tone for 50 msec or
a DST message. The voice
path is muted while sending
ST.
The telephone drops the
voice channel and keys up
on the new voice channel
frequency. The telephone
sends the newly assigned
SAT (DSAT).
DATA
FOVC
(D)ST +
SAT
REVC
(D)SAT
REVC
Switch / Cell Site
VOICE + (D)SAT
FOVC & REVC
The cell site monitors the cellular
telephone's signal strength. When
the signal strength falls below the
allowed minimum (typically
-100 dBm at the highest power
step), the cell site informs the
switch of the need for a handoff.
The switch orders surrounding cell
sites to measure the cellular
telephone's signal strength. The
switch assigns a new cell site,
voice channel, and SAT (DSAT)
based on the highest signal
strength, and informs both cell
sites. The old cell site mutes the
voice path and sends a data burst
with handoff information to the
cellular telephone
The originally assigned cell site
receives the signaling tone
(DST) and informs the switch to
continue with the handoff.
The switch moves the landline to the
voice channel at the new cell site.
The new cell site receives the
correct SAT (DSAT) and unmutes
the voice path.
Conversation in progress.
The voice path is unmuted.
14
Conversation in progress.
The voice path is unmuted.
VOICE + (D)SAT
FOVC & REVC
©2000 Motorola, Inc.
Conversation in progress.
The voice path is unmuted.
Cellular OverviewService Manual
Analog Cellular
Call Termination
signalling tone burst for 1.8 seconds, indicat-
ing a call termination request to the switch.
When the call is terminated by the landline
caller (not the cellular telephone user), the
central controller (switch) issues a release
order to the subscriber unit. The cellular
telephone acknowledges with a 10kHz signalling tone burst for 1.8 seconds and the
In either case after call termination, the cel-
lular telephone goes back to rescan the na-
tionwide set of forward controlchannels and
repeats the Going into Service process it per-
formed at first turn-on to re-establish itself
on a paging channel.
cellular telephone ceases transmission.
If the call was terminated by the cellular telephone user, the telephone generates a 10kHz
Figure 10. Cellular Telephone Call Processing Termination
Cellular Telephone
Switch / Cell Site
Landline Network
Conversation in progress.
Voice path is unmuted.
The cellular telephone user
hangs up or hits the END key to
terminate the call.
The cellular telephone sends a
1.8 second burst of 10 kHz
signaling tone or a DST vector
to the cell site, then stops
sending SAT (DST).
The cellular telephone rescans
the access / paging channels
for the strongest signal and
decodes data. The cellular
telephone responds to
requests for data.
(D)ST +
(D)SAT
REVC
DATA
FOCC
&
RECC
VOICE + (D)SAT
FOVC & REVC
The cell site receives the
signaling tone (DST) and
notifies the switch of the
disconnect. The cell site
mutes the audio path on the
voice channel.
The switch informs the TelCo
of the disconnect and the
Overhead data sent out on
12
landline is released.
the control channel.
Conversation in progress.
The landline is released.
©2000 Motorola, Inc.
15
TDMA T2290/T2297Cellular Overview
16
©2000 Motorola, Inc.
Cellular OverviewService Manual
Digital Cellular
Digital Cellular
Multiplexing
Using a single frequency to carry two or more
communication links (e.g., conversations) is
called multiplexing. There are two types of
multiplexing that are feasible for cellular:
code division multiplexing and time division
multiplexing. Both code division multiplexing and time division multiplexing digitize
voice before transmitting the signal. Another
type of multiplexing, frequency division multiplexing, was briefly considered, then abandoned. We will deal with each type of multiplexing separately.
FDMA (Frequency Division Multiple
Access)
Frequency Division Multiple Access
(FDMA) uses two or more modulated sub-
carriers to modu-
late a third true carrier simultaneously.
While as many as six communication links
can be accommodated on a single frequency
with FDMA, the bandwidth requirements are
enormous. Given the relatively small 30 kHz
bandwidth of cellular, FDMA was never a
contender for improving the load carrying
capacity of cellular systems. Also, it should
be pointed out that FDMA is not necessarily
digital.
Digitizing Voice
If a person speaks into a microphone, a trans-
ducer in the microphone converts the me-
chanical air movements produced by the
person’s vocal cords into varying voltages. If
an oscilloscope probe is connected to the out-
put from a microphone, a varying voltage
Figure 11. Digitizing Voice
Amplitude (voltage)
Time
©2000 Motorola, Inc.
17
Digital Cellular
TDMA T2290/T2297Cellular Overview
line, such as that shown in the accompanying illustration, will be produced.
If the varying voltages are sampled at some
rate, the instantaneous voltages can be quantified. Let’s say we want to quantify measurements from values of zero to 255 (the
maximum value a binary byte can hold). The
value of 255 would represent the highest possible voltage we could expect from voice, and
zero would represent silence. Each discrete
integer between zero and 255 would represent a particular voltage, typically presented
in binary form.Because of the redundancies
of speech and the inability of the human ear
to detect more than a fraction of the intelligence in speech, it is possible to sample a
small portion of the sound produced by a person speaking, reproduce that sound at either
a later time or another place, then filter the
resulting reproduction to produce a “sound”
that is indistinguishable from the original
source.
audio.
TDMA (Time Division Multiple Access)
Time Division Multiple Access (TDMA) today provides a times-3 increase in the number of communication links a channel can
carry (just like NAMPS). Eventually TDMA
is expected to take full advantage of all six
time slots, allowing for six communications
links in the bandwidth of a conventional
AMPS channel.
TDMA, like CDMA, employs a form of phase
shift keying to represent symbols. However,
TDMA also compresses the digitized signal,
making use of predictive algorithms to reduce
the number of symbols actually transmitted.
Digitization and TDMA
Here three conversations, represented by
In the illustration on page 1 - 19 we saw how
speech could be sampled at some rate. Suppose we take only one of every three samples.
If our sampling rate is fast enough, and if we
can compress the samples, it turns out that
we can interleave several different conversations (communication links) on a single frequency. However, we also have to provide
some mechanism for ensuring that the transmitter and receiver are in synchronization,
and we have to provide for some alternative
to the control and response tones used in conventional AMPS. All of these non-voice signals are digital and take time from the assigned time slot, leaving only a relatively
small amount of time to represent voice. For
this reason the digital receiver has to filter
the audio to closely approximate the original
Figure 12. Digitization and TDMA
tude
A
Ampli
Time
B
C
18
©2000 Motorola, Inc.
Cellular OverviewService Manual
ABCAB
C
Slot1Slot2Slot3Slot4Slot5Slot
Digital Cellular
voice samples as viewed on oscilloscopes, are
clearly shown to be nothing more than varying voltages produced by microphones. Instantaneous samples are discrete voltages.
It has been shown that if the sampling rate
is fast enough, it is possible to make a faithful representation of each conversation.
If these samples are then compressed, it is
possible for more than a single conversation
to occur on a single medium (such as a radio
frequency) by sharing time slots. Here we
see three conversations being shared on six
time slots. The conversations shown are compressed sampled analog audio, not yet digitized.
Figure 13. Slot Assignments
Slot1Slot2Slot3Slot4Slot5Slot
6
Figure 14. Digitization of Voltage
6
2 volts
1.75 volts
1.5 volts
1.25 volts
1 volt
.75 volt
.5 volt
.25 volt
0 volt
A B C AA B C
The very first instantaneous sample has
an amplitude of .625 volts represented by
01001111 (79 decimal).
This instantaneous sample has an amplitude
of 1.125 volts represented by 10001111
(143 decimal).
Conventional Radio
Radio uses transmitters to convert speech to
radio energy and receivers to convert radio
energy back to speech. In conventional analog radio, speech is converted into varying
voltages called audio by a microphone. The
Digitization of Voltage
A byte, consisting of 8 bits, holds 256 possible numbers (0 through 255). If the maximum voltage we might expect from our voice
samples is 2 volts, we can arbitrarily match
those voltages proportionally to our byte. The
result is a binary string representing voltages. We now have digital voice.
©2000 Motorola, Inc.
Figure 15. Convetional Radio
Microphone Speaker
IF
audio is mixed with a carrier frequency, amplified, and propagated through space as radio energy by an antenna. At the remote receiver an antenna converts the received radio energy to varying voltages at radio frequencies. The RF energy is beat against the
output from a local oscillator to produce a
difference frequency called the intermediate
19
Digital Cellular
frequency. The IF is processed in the IF strip,
which provides filtering and amplification.
A discriminator retrieves audio from the IF
and the varying voltages of the audio are used
to drive a speaker
TDMA Radio
TDMA radios use the same circuitry as analog radios, for the most part, but also have
additional circuitry to convert analog audio
to digitized form and vice versa, and to select the appropriate time slot.
Figure 16. TDMA Radio
1010101010101 01010 101
Processing
Network
101
0101010101010 10101 010
010
1010101010101 01010 101
101
0101010101010 10101 010
010
101
Processing
Network
TDMA T2290/T2297Cellular Overview
A/D
Slot selector
Slot selector
ZIF
D/A
20
©2000 Motorola, Inc.
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