Post on 08-Apr-2018
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Zarlink Semiconductor Inc.Zarlink, ZL and the Zarlink Semiconductor logo are trademarks of Zarlink Semiconductor Inc.
Copyright 2003-2005, Zarlink Semiconductor Inc. All Rights Reserved.
Contents
1.0 Introduction
2.0 What are the requirements for a D.A.A?2.1 Functional Block Description
2.1.1 DC Loop Termination
2.1.2 Line Impedance Matching
2.1.3 2-4 Wire Conversion
2.1.4 Supervisory Features
2.1.5 Protection
2.1.6 Line Isolation and Regulatory Require-
ments
2.1.7 RFI/EMC and Power Supply Design
Considerations
3.0 Zarlink Semiconductor DAAs
4.0 MH88422 Data Access Arrangement4.1 General Considerations
4.2 Applications Example
4.2.1 Gain Adjustment
4.2.2 Ringing detection
5.0 MH88435& MH88437 Data Access Arrange-
ments
5.1 Device Set up and Programming
5.1.1 DC Mask Programming
5.1.2 Network Balance Impedance
5.1.3 Detection of Line Reversals
5.1.4 Gain Adjustment
5.1.5 The Loop Pin
6.0 MH88437 Data Access Arrangements
6.1 Device Differences
6.2 Device set up and programming
7.0 Using the MH88437 DAA with CTR21
7.1 Points of Note when Designing for CTR21
1.0 Introduction
The purpose of this application note is to provide
information on the operation and application of Zarlink
Semiconductors range of Data Access Arrangement
(DAA) devices.
DAAs can be used in a wide range of analog data and
voice transmission equipment, such as modems, Fax
machines, Electronic Point of Sale terminals and Set
Top Boxes. Figure 1 gives an example of a typical
modem system.
Zarlink Semiconductor DAAs can be used to provide a
complete interface between analog transmission
equipment and a telephone line. All functions areintegrated into a single module, providing high voltage
isolation, very high reliability and optimum circuit
design needing few external components.
The design requirements of the DAA have, over time,
become more stringent as data rates have increased
and markets have become global. Zarlink
Semiconductors range of components has been
developed to embrace the new requirements and are
being used by customers all over the world. This
application note will assist in using the Zarlink DAAs
with any grounded modem or other analog
transmission systems.
NOTE: Set top box is the name given to the decoder
units used with Cable and Satellite systems and
normally located with the TV sets.
January 2005
MSAN-154
Zarlink Data Access ArrangementDevices
Application Note
Figure 1 - Typical Modem System
ModemControl &
Data Pump
DATA SOURCE
Telephone
Line
LoopControl/
Supervision
DataAccess
Arrangement
System Equipment
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Figure 2 - DAA Block Diagram
2.0 What are the requirements for a D.A.A?
2.1 Functional Block Description
The DAA has to perform a number of distinct functions in order to provide the level of functionality needed in
terminal equipment. Many of these functions have regulatory standards applied to them. Zarlink DAAs simplify
designs and provide a faster route to gaining regulatory approvals.
Figure 2 shows a schematic with the key features required of a DAA.
2.1.1 DC Loop Termination
The DAA is required to terminate the telephone line in the appropriate way dependent upon the status of the call. In
the on-hook state a high impedance must be applied to the line, i.e., no DC current flows in the loop. Each DAA
presents a high impedance to ground which is product related. (Refer to relevant product data).
An incoming call is detected by the presence of ringing, indicated on the ring detection pin. To answer the call a DC
termination is applied to the line by activation of the loop control pin, signalling to the exchange that a subscriber
has gone off-hook and is ready to set up the equipment initialization.
Where the call is initiated by the subscriber the DC termination is applied to the line, causing loop current to flow,
signalling to the exchange the initiation of the call.
Dialling can be performed either by using Dual Tone Multi Frequency (DTMF) signalling or by dial pulsing.
For the latter, the loop control pin can be used to interrupt loop current for pulse dialling.
Most countries have different DC mask requirements that need to be met. The term DC Mask relates to the current
vs voltage characteristics of the off-hook terminal equipment. These are set on the country variants of the MH88422
but can be changed on the MH88435/MH88437 with external components. The DC characteristics and
programming component values can be found in both data sheets.
Active
Termination
Barrier (Isolation)
2-4 Wire
Conversion
Impedance
Matching
Loop Monitor
and
Supervision
TIP
RING
VX
VR
Ringing Detect
Loop Current
DetectLoop Control
P
S
T
N
User
System
Data
Source
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At the end of a call the DC load is removed by the DAA and the termination returns to a high impedance state.
2.1.2 Line Impedance Matching
To obtain optimum performance on a transmission link it is necessary to match the AC characteristics of the DAA to
those of the line. The characteristics of the line can vary according to the regulatory standards of a given country or
network operator.Two impedances are usually stated, these are the line characteristic impedance and the network balance
impedance.
The line impedance of the DAA must be matched by the termination impedance. A mismatch will cause losses and
echoes on the link, potentially increasing error rate, reducing transmission speed and even the interruption of
transmission. The line impedance can be resistive or complex.
The network balance impedance is chosen to ensure that data transmitted by the subscriber is not reflected back
into the DAA. This can be equal to the line impedance or a different impedance according to regulatory or operating
requirements.
For DAAs which must be used in international applications there must be a method of programming these
parameters. This method varies, dependent on the DAA used. Compromise values can be attached to the DAA,
for multi-country approvals and are available.
2.1.3 2-4 Wire Conversion
The DAA interfaces to a 2 wire telephone line which is a full duplex link. The DAA must extract from the line a
Transmit signal and place onto the line a Receive signal. This has to be done to enable the connection to other
devices such as Modem chipsets and DSP circuits which use a 4 wire connection.
Note: All Zarlink Semiconductor Analog Line Interface product information refers to "Transmit" as the 4W output
from a 2-4 wire converter and to "Receive" as the 4W input to a 2-4 wire converter.
Historically this function has been performed by a hybrid transformer, which provides good isolation but is bulky and
difficult to manufacture. Modern designs use active components to achieve this function, providing low cost and
high performance in a very small package.
Central to the design of a 2 to 4 wire converter is the need to cancel the transmitted signal on the telephone line. If
there were no cancellations, this signal appears at the input of the DAA and could be interpreted by the DAA as a
signal from the far end of the link. The measure of the ability of the DAA to cancel this signal is known as Trans
Hybrid Loss (THL).
Good THL is achieved by accurate matching of the Network balance impedance to the line impedances and is
usually stated for a given impedance and band of frequencies, as line length and discontinuities in the line will affect
performance. For operation with a variety of line lengths a compromise impedance can be used to give an
adequate THL, this removes the need to switch the balance impedance e.g., AT&T compromise.
2.1.4 Supervisory Features
The DAA must be capable of monitoring and controlling the line conditions for efficient management of the link. The
key control feature which is needed is the loop switch function. This is used to apply the correct termination to the
line and to provide pulse dialling facilities.
Line monitoring is needed to complete the signalling link from the far end. The signals which must be detected are
ringing, line reversals and the presence of devices connected to the line e.g. a telephone set in parallel with the
DAA. The nature of supervisory signals varies according to the service providers specification. External circuitry
may be required to detect line reversals and/or parallel phones. Not all functions are provided on all DAAs.
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Responses to changes in the line signalling conditions are generated by the controlling system processor, which
implements the appropriate protocols either through the DAAs line control facilities or the use of modem command
sets.
2.1.5 Protection
The use of active components in the DAA means that adequate protection from high voltages must beprovided. The high voltages can result from lightning strikes or fault conditions e.g., mains cables shorting to the
telephone line.
Specifications for protection are often particular to the PTT or service provider, but international standards do exist
such as ITU-T K.20.
Protection can be provided by components such as Fold Back diodes, Positive Temperature Coefficient Resistors
(PTCs), Transorbs and fuses.
It is not possible to show protection circuits to meet all requirements in this document, and due to the dynamic
nature of regulatory standards Zarlink Semiconductor recommends that users of Zarlink DAAs consult with
regulatory standards, standards bodies and approved test laboratories. However, an example is shown below of
circuits to meet specific needs (see Figure 3).
Figure 3 - Protection Circuit
Figure 4 - DAA and RFI Filters
2.1.6 Line Isolation and Regulatory Requirements
The DAA must provide isolation between the telephone line and the subscribers equipment. The isolation barrier
can be at various positions in the equipment, for example, in the power supply, in the DAA or a combination of
these. The precise method depends upon the type of equipment being built and the country in which it will operate.
TIP
RING
TR600-165Resettable
Fuses
Foldback
Diode
D1
D.A.A.
MH884XX
Circuit to meet UL1459 (50A.19)
MH88422
D1 = 190V
Teccor P2000A
MH88435 & 437
D1 = Teccor P3100SB
or P2703SB
Tip
Ring
MH8843X
To The Network
470H
470H
2200pFX7R
3kV
2200pF
X7R3kV
= earth (ground)
TIP
RING
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International standards are in operation for the line isolation, the most common being IEC 950, which is adopted
as EN60950 in Europe and UL1950 in North America. This defines categories of levels of isolation which must be
provided.
Note: In order to meet functional requirements the DAAs AGND may need to be connected to earth. The main
purpose of this is to reduce 50/60 Hz common mode signals which are associated with floating power supplies.
2.1.7 RFI/EMC and Power Supply Design Considerations
All of the DAAs mentioned in this application note will have to be protected from RFI(EMC) radiations that might be
generated by the PSTN. In some instances this may be a mandatory requirement, but in general failure to protect
the terminal equipment may result in the degradation of functionality of the DAA. RFI filters should not pass
frequencies above 150kHz, and should be fitted as closely to the telephone socket as possible (Figure 4 shows a
typical low pass configuration). The dielectric of the capacitors used must be able to withstand 1k5V, since these
will form a path to ground.
Even with the filters in place, the design and layout of a line card can still have a great effect upon
functionality with respect to noise and power supply interface. Care should be taken that other interface lines into
the application do not route unwanted RFI or transient noise that will be coupled across to the Tip and Ring lines.
This will prevent the degradation of the signal being received from the network.
Power Supply switching noise should be kept to a minimum, and power distribution to fast switching needs to be
via a low impedance path, with adequate local current sourcing available. The supply lines to the application
hosting the DAA should not have RFI levels present which exceed 100m Vrms over the frequency range 150kHz to
1000MHz.
Table 1 - Zarlink Semiconductor D.A.A.s
Note 1. Meets requirements of France and Germany in addition to the country requirements the MH88435 meets.
3.0 Zarlink Semiconductor DAAs
Zarlink Semiconductor DAAs have been designed to work as plug in modules, simplifying system design and
reducing overall cost.
They have developed along with changing standards and transmission speed and are still evolving. Table 1 shows
a summary of the key differences between the various product families.
Key Features MH88422 MH88435 MH88437
Reinforced Barrier 3
Supplementary Barrier 3 3
FCC Pt 68 isolation 3 3 3
Integral Loop Switch 3 3 3
Maximum Data Rate 9k6 33k6 (56k) 33k6 (56k)
Full Duplex Voice Capability 3 3
On Hook Reception 3 3
Programmable Impedances 3 3
Country Variants 3
Programmable DC characteristics 3 Note 1
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The family of products is continually being added to. We recommend that you contact Zarlink Semiconductor or one
of our representatives or distributors for latest information on available products, visit our Web site first.
4.0 MH88422 Data Access Arrangement
Device Description
The MH88422 is a DAA designed for V.29 applications where a reinforced barrier is required. It provides the 3kV
isolation barrier, 2-4 wire conversion function, the loop switch and is supplied as country specific variants as shown
below.
The device is a 26 pin Dual in Line packaged product.
4.1 General Considerations
The MH88422 has been designed to minimize the number of external components which are needed. As a
minimum the components shown in Figure 5 will be needed.
D1 is for protection from high voltage spikes, particularly from lightning strikes. C1 is a decoupling capacitor, to
remove unwanted noise from the power supply. C2 forms part of the dummy ringer circuit.
A dummy ringer is needed in order to provide the correct ringer load to the network, a load which varies between
countries. The resistive element of the dummy ringer is on board the MH88422, but this can be altered externally by
modifying the load between tip and ring. Refer to the relevant regulatory specs for different dummy ringer
requirements.
4.2 Applications Example
Security System
Warden Call and Security Systems often use dial up modem technology to provide data transfer capability to a
variety of different networks.
Device # Countries
MH88422-1 Germany (1TR2), Spain, Australia, Switzerland,
South Africa
MH88422BD-1 Germany (ZV5)
MH88422-2 North America, Far East and other countriesusing 600W
MH88422-3 United Kingdom, New Zealand
Note: The relevant country approval specification must be checked toverify compliance of the MH88422 part.
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Figure 5 - Typical MH88422 Application Circuit
Typically such a system would, in the case of an emergency, first dial the security service provider, often the Police,
or medical assistance. This is done through the following sequence of events:
1. The terminal moves from the on hook state to the off hook state through the closing of the loop switch inthe DAA.
2. Once dial tone has been detected a call will be made by transmitting DTMF tones to the Central Office or
PABX.3. If a busy tone is detected or call not answered then the sequence will be aborted through moving back to
the on hook state and the call will recommence.
4. When the call is answered and an acknowledgment is received the terminal will move to a data transfermode, when information on the nature of the emergency will be transmitted to the control centre.Appropriate action will then be taken.
A call can also be initiated from the control centre in order to interrogate the terminal, ensuring that it is functional
and down loading software upgrades. If this is the case then the MH88422 will detect the ringing signal allowing the
controlling processor to take the terminal off hook and receive the data transfer.
4.2.1 Gain Adjustment
Figure 6 shows a typical set up for an application with a phone connected in parallel for Germany.
Transmit gain adjustment is provided by resistors R3 and R4. The gain is calculated using the following equation:
GainTx = 20log[R4/(R3+R4)] -0.4dB
Note, (R3 + R4) > 2k
TIP
RLS
TF
TXIN
RING
VX
VR
RVLC
LC
AGND
VDD
TIP
RING
C1
+5V
1
3
5
7
11
13
16
18
20
24
26AudioInput
Audio
Ring Voltage & LoopCurrent Detect Output
Loop Control Input
MH88422
+
R3
R2
R1
Protection
Circuit
Output
C3
C4
C2
Notes :
1) R1, R2: Transmit Gain Resistors2) R3 : Receive Gain Resistor3) C1 : 10F 6V Tantalum4) C2 : Dummy Ringer Capacitor5) C3, C4 : 10F AC coupling Capacitors
6) D1 Protection Circuit : See 2.1.5
D1
= earth (ground)
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Receive gain is set by R5. The receive gain is calculated using the following equation:
Gain Rx = 20log [47k/(47k+R5)] +3.5dB
These resistors must be fitted to prevent overloading of the output signal.
Figure 6 - Typical MH88422BD-1 Application
4.2.2 Ringing detection
The MH88422 provides the circuitry required to signal the presence of the ringing signal. The ringing signal
detection threshold and dummy ringer loads are defined in the relevant regulatory standards.
The MH88422 variants are designed to meet certain regulatory requirements for ringing detection by simplyconnecting together the relevant pins on the device and using a specified dummy ringer capacitor. However, the
user can adjust the threshold and dummy ringer load by using external components.
In Figure 6, R2 is shown fitted; this component allows external adjustment of the Ring detection threshold level. By
fitting R2 in parallel with R1 the ring detection level is increased from the minimum level quoted in the data sheet.
When choosing the value for R2 it should be noted that R7 and C2 which form the dummy ringer will also affect the
detection threshold value.
Note: Zarlink Semiconductor recommends consulting the regulatory standards and engaging the service of an
approvals testing facility before attempting to adjust the dummy ringer and ringing detection thresholds.
NOTES:
R3 = R4 = 2K2 (Typical value)
R5 = 100K (Typical value)
R6 = 200R - used to set parallelphone detection threshold
C1 = 10F 6V
C2 = 470nF
C3 = C4 =10F 10V
C6 = C7 = 22nF @ 16kHz
L1 = L2 = 4.7mH
D1 = Foldback Diode,
P2000AA61 (Teccor),
D2 = 1N4004
K1 = Electromechanical relay -
Must be compliant with reinforcedbarrier requirements. (K1a changeover
K1b normally open).
R2 = Ring Detection thresholdadjust resistor
Tip
PABX
Ring
D1
R6
K1a
R2 L2
C7
C2
L1
C6
D2 K1K1b
Tip Vx
RLS
MH88422 BD-1
Vr
TXIN
TF
RVLC
LC
VDD AGND
Microprocessor
R3 C4
R4
R5
+5V
C1
Modem
Data
Pump
+
+
+
C3
C7 = 29nF @ 12kHz
= earth (ground)
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5.0 MH88435& MH88437 Data Access Arrangements
Device Description
The MH88435/7 are DAAs designed as Telecom Network Voltage (T.N.V.) circuits for V.34 and V.34+ applications
where a barrier is required to comply with the supplementary barrier requirements of EN60950 and UL1950.
In addition to the isolation, the MH88435/7 provide the 2-4 wire conversion function and an integral loop switch.
Additionally the MH88435/7 have been designed to meet the network requirements of most administrations
worldwide and can be programmed to meet various line impedance and balance networks and DC templates.
The MH88437 is a superset of the MH88435 in that it will meet the same country requirements and in addition meet
specific requirements for France and Germany. These are detailed in the respective data sheets.
The devices are 28 pin Dual in Line packaged products and are available in surface mount or through hole format.
5.1 Device Set up and Programming
The MH88435/7 have many programmable features and these are described below. The set up of the ringing
sensitivity, line impedance, gain and protection circuits are implemented in the same way as was described for the
MH88434.
The programming of line impedance is done by connecting a network from ZA to ground. A table of networks
suitable for many countries is shown in Table 2.
An approximate value for other countries can be found by using the calculation given in the data sheet.
Zin = Zext + Zint
10
where Zext = external network connected between Za and AGND and Zin = 1.3k (internal resistance).
Refer to Table 2.
5.1.1 DC Mask Programming
The DC conditions which must be adhered to vary depending upon the country in which the DAA is being used. For
this reason the MH88435/7 can be programmed with the use of resistors outside of the device. This programming
feature should rarely be needed but provides the user with the flexibility to meet almost any requirement. France
requires that the loop current drawn by the DAA does not exceed 60mA, the MH88437 must be used to achieve this
where this feature can be met by setting CL to logic 0. The current limit is also required for CTR21.
5.1.2 Network Balance Impedance
The Network balance impedance is set by connecting a network between the NB1 and NB2 pins. Failure to
correctly match the network balance impedance will result in a degradation of the Trans Hybrid Loss performance
and as a result data transmission capability.
If the balance impedance is the same as the line impedance then a 15k resistor should be connected for the
MH88435, or a 16k resistor should be connected for the MH88437. For values which differ from the line
impedance then the correct network should be selected. Table 2 shows some typical network requirements.
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Table 2 - Programming Components
Note 1. For the MH88435 this value is 15k while for the MH88437 this value is 16kNote 2. Use MH88437 for this countryNote 3. NF = Not FittedNote 4. For the MH88435 this value is 2k0 while for the MH88437 this value is 910R
5.1.3 Detection of Line Reversals
If the detection of line reversals is required, the use of the circuitry in Figure 7 will be required. LR will be at +5V
when the polarity of the loop is positive forward battery and 0V when the loop is in reverse battery.
IC1 = LM339
Figure 7 - Line Reversal Detection Circuit with Connections to the MH88435/7 shown
5.1.4 Gain Adjustment
The transmit gain of the MH88435/7 is 0dB. Transmit gain adjustment is provided by resistors as shown in Figure 8,
which form a simple potential divider. The gain is calculated using the following equation:
Gain Tx = 20 log R4/(R4 + R3)
Rpext Rsext Cpext ZOUT ZBAL RNS1 RNS2 RNP CNP
0R 4k7 NF 600R ATT Compromise 8K2 2K2 2K0Note 4
33nF
7K5 1K4 15nF CTR21Note 2
Equal to Zout 16K 0R NF NF
8K2 910R 10nF GermanyBAPTZV5
Note 2
Equal to Zout 15KNote 1
0R NF NF
0R 4K7 NF 600R 600R 15k
Note 1
0R NF NF
5K1 2K2 33nF UK BS6305 Equal to Zout 15kNote 1
0R NF NF
8K2 820R 15nF France*1Note 2
16k 0R NF NF
= earth (ground)
-
+
LR
+5V +5V
15K
Pin 11Loop
Pin 10VBIAS
IC1
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Note: (R4 + R3) >2k. Unlike the MH88422 and MH88434 these components do not need to be fitted unless gain
adjustment is required.
The receive gain is also 0dB, but can be adjusted by fitting R5 & R6. These resistors are in series with the device
input impedance, formed by the input resistors for VR+ & VR- feeding into an amplifier stage. The value for R5 and
R6 must be equal when used in a differential mode. The formula for calculating the gain is:
Gain Tx = 20 log 47k/(47k + R5).
It is usually not necessary to set the gain externally as this can be done through the modem chip set in which case
R5 & R6 are not fitted.
Figure 8 - Typical Application Circuit
TIP
NB2RING
VX
VR+
RV
LC
AGND
VCC
TIP
RING
C2
+5V
9
8
6
16
5
3
28
AnalogInput
Analog
Ringing Voltage Detect Output
Loop Control Input
MH88437
+
OutputC4
C1
Notes:
R1 & C1: Dummy Ringer, country specific
ZA
7
Zext
R2: DC Mask Resistor 82 k typical
R1
25 24
VLOOP1
VLO
OP2
VR-4 Analog
Input
R2
LCD 15Loop Current Detect Output
NB1
ZB: Network Balance Impedance
R3
R5
R6
R4
R5 = R6: Receive Gain Resistors typically 100 k
R3 & R4: Transmit Gain Resistors 2 k2
C3 +
10
VBIAS
typically 0.39 F, 250 V & 3 k
C2 & C3 = 10 F 6 VC7 & C8 = 39 nF for 12 kHz filter and 22 nF for16 KHz filter. These can be left off if meter pulse
filtering not required.Zext: External Impedance
D1 Zener Diode 9V1 (x2)L1, L2 = 4.7mH RDC
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5.1.5 The Loop Pin
The loop pin output voltage, VLOOP, is proportional to the line voltage across Tip and Ring V(t-r), scaled down by a
factor of 50 and offset by VBIAS which is approximately 2.0V.
The formula is therefore:
V(t-r) = (VLOOP - VBIAS) x 50
6.0 MH88437 Data Access Arrangements
There are some differences between the two DAAs which are detailed further in this section.
6.1 Device Differences
The MH88437 is a pin for pin compatible part with the MH88435. In addition to the features of the MH88435, the
MH88437 will:
Meet the French current limit specification of 60mA
Meet the German dial pulse requirement of BAPT 223 ZV5
6.2 Device set up and programming
The programmable features of the MH88437 are the same as the MH88435, the only exceptions are:
Network balance impedance components are as defined in Table 2.
A pin previously not used, CL, is used to control the French current limit. For countries not requiring thisfeature the pin should be set to logic 1.
For details on the countries that the MH88435/7 are suitable for, please refer to the individual data sheets.
7.0 Using the MH88437 DAA with CTR21
As of July 20th 1998 TBR21 became CTR21, giving mandatory access to the PSTN data applications in all EC
countries (plus Finland, Iceland, Israel, Norway and Switzerland). Even though this CTR is enforceable for terminal
equipment, the document has no scope to alter the equipment within the Central Office in each of these countries,
that will eventually interface with your application. This leads to many problems for designers who wish to use
CTR21 as a common licence for connection in Europe.
To aid a design using this approach into Europe Zarlink advise that, applications using the MH88437 are still
designed to meet the country specific specifications, in addition to the CTR21 document. This is necessary due to
the many different AC and DC termination requirements.
The line conditioning components below (Figure 9) when used in conjunction with the logic table 2, are capable of
providing regulatory approval to the standards listed for each country.
7.1 Points of Note when Designing for CTR21
1. CTR21 has no provision for equipment utilising Pulse or Loop Disconnect dialling. Any application declaring its
use in countries other than Holland and Switzerland will have to adopt the national route for approval.
2. When designing an application for use with CTR21, refer to the advisory notes EG201 121 issued by ETSI.
Although these notes are not a legal requirement their content is informative.
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3. Finland, Iceland, Israel, Norway and Switzerland are not members of the EC, but they have chosen the to align
themselves to CTR21. This means that each of them can choose the test house that they will accept a report
from. Before beginning the process of approval to CTR21 it is prudent to investigate which test houses can issue
a recognised report for these countries.
4. To pass the Norwegian National DC mask using the application circuit (Figure 11), L1 and L2 should be replaced
with 0 links.
5. CTR21 makes no mention of Meter Pulse Filters but under both the German and Swiss national requirements, a
high impedance to 12kHz and 16kHz meter pulses is mandatory. The value of RDC for L1 and L2 should be
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MSAN-154 Application Note
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Figure 9 - Output and Network Balance Impedance Setting Networks
Table 3 - Programming Conditions for Various Approvals
Table 4 - Programming Conditions Advisable for Additional Country Approval
Country Approval Spec. CL SW1 Position
Denmark CTR21 0 2
France B11 23A 0 1
Germany BAPT223 ZV5 1 2
Holland T11 1 1
Luxembourg CTR21 0 2
Switzerland SR.784.103.12/2.2 1 2
Sweden CTR21 0 2
U.K. CTR21 0 2
Country Approval Spec. CL SW1 Position
Finland NET 4 0 1
Italy NET 4 1 1
Norway NET 4 1 2
Spain CTR21 0 2
Portugal NET 4 1 1
NB 1
NB 2
ZA
Rpext Cpext
RNS1
RNS2CNP
RNP
MH88435/7
Rsext
= earth (ground)
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MSAN-154 Application Note
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Figure 10 - MH88437 V/I Characteristics During Current Limit (shown with CTR21 Mask)
X
X X
X
(14.1,4.8)(21,6.2)
(43,13)
(56,37)
MH88437 Response
40V
4.5
9
020 42 50 60
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MSAN-154 Application Note
16Zarlink Semiconductor Inc.
Figure 11 - CTR21 Application Drawing (with a 600R Option and Meter Pulse Filters)
15k
220k
70k
1 2
SW1
750R
15nF6k24k7
ZA
LOOP
RS
NETBAL 2
NETBAL 1
CLTip
Vloop1
Vloop2
Pin21Pin 22
Ring
175pF
L1 = 100uH
0.39uF C1
6V2 CR1
3k9 R1
MH88437
To PSTN
= earth (ground)
TIP
RING
C1
C2
0.1uF
L2 = 100uH
9V1
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