ETS1201 Series Fixed Wireless Terminal Maintenance Manual

ETS1201 Fixed Wireless Terminal Maintenance Manual

ContentsChapter 1 FWT Working Principles and Parameters.................................................................1 1.1 Hardware Structure and Working Principles .....................................................................1 1.2 Hardware Structure Description of FWT Major Functional Modules..................................2 1.2.1 Hardware Structure of the TCPU............................................................................2 1.2.2 Hardware Structure of the TUTU............................................................................4 1.3 Function Description of FWT Major Functional Modules...................................................5 1.3.1 User Interface Subsystem .....................................................................................5 1.3.2 Power Supply and Power Supply Management Subsystem.................................14 1.3.3 QSC6020 Subsystem...........................................................................................18 1.3.4 RF Subsystem......................................................................................................19 1.4 Parameter Index .............................................................................................................21 Chapter 2 Guide to FWT Assembly/Disassembly .....................................................................1 2.1 Assembly of FWT .............................................................................................................1 2.2 Disassembly of FWT ........................................................................................................3 Chapter 3 Repair Process and Troubleshooting ......................................................................1 3.1 Repair Process .................................................................................................................1 3.1.1 Repair Process of Baseband Processing Interface Module Failure .......................1 3.1.2 Repair Process of RF Processing Module Failure ................................................3 3.2 Troubleshooting................................................................................................................5 Chapter 4 List of Damageable Spare Parts ...............................................................................1

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Chapter 1 FWT Working Principles and Parameters1.1 Hardware Structure and Working Principles

Figure 1.1 Hardware structure of ETS1201FWT Huawei ETS1201 Fixed Wireless Terminal (FWT) consists of two boards. One is the FWT communication process unit (TCPU) and the other is the interface processing unit (TUTU). 1.1 shows the hardware structure of the FWT. The TCPU is the core unit of the FWT. It consists of the RF transceiver unit, central processing unit, power unit, and power monitoring unit. The TUTU and TCPU are connected through a 72-pin solder cup. (There are 72 solder cups on the four borders of the TCPU. They are soldered to TUTU like a fort. ) The TUTU provides the function to connect to the TCPU. It provides various interfaces, including the USB Interface. External DC power inlet, battery interface, power switch, POTS interface, extended facsimile interface, indicator light interface, antenna interface, and R-UIM interface.

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1.2 Hardware Structure Description of FWT Major Functional ModulesThe hardware system of the FWT consists of two boards. They are TCPU and TUTU. The FWT functional modules include the user subsystem, power subsystem, QSC6020 subsystem, and RF subsystem. Each board has its own functional modules. Classified by function, the TCPU functional modules include the QSC6020 subsystem, power and power management module part, RF subsystem, and TUTU interface module. The TUTU functional modules include:

User subsystem, which consists of the Subscriber Line Interface Circuit (SLIC) interface module, R-UIM card interface module, extended facsimile interface module, indicator module, and environment variable monitoring module.

Power and power management module part, which consists of the primary power interface module. protection module, primary power detection module, battery charging/discharging module, DC/DC power module, and the on/off control

1.2.1 Hardware Structure of the TCPU

Figure 1.2 Hardware structure of the TCPU board For the ETS1201, the major difference of the hardware part is the frequency of the RF module on the TCPU board. The ETS1201 uses the 800 MHz RF module. The structures of TCPU boards working on different frequencies are the same. The TCPU board can be divided into four parts: QSC6020 subsystem, power and power management module part, RF subsystem, and TUTU interface module, as shown in 1.2.1. The QSC6020 subsystem consists of the speech codec unit, baseband signal processing unit, and the CPU system used to run the protocol software. All these functional units are integrated in the QSC6020 chip. The speech codec unit realizes

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the compressed coding of 64 kbps speed data stream, for example EVRC coding, so that the data can be transmitted over the radio network. The baseband signal processing unit implements the baseband modulation and demodulation and channel codec functions. It also consists of the CPU system used to run the protocol software and applications. Besides, this subsystem also contains the FLASH used to store the software and the SRAM used to run the software. The power and power management module part realizes functions related to the system power supply and power management. The RF subsystem consists of the RF processing unit and the antenna feeder system. The RF signal processing unit realizes the modulation/demodulation of baseband signals, power amplification, and up/down-convert functions. It converts the baseband signals into the RF signals for radio transmission, or converts the RF signals into the baseband signals. The interface involved in the CDMA2000 1x Um interface. The TUTU board provides the power interface, PCM interface, USB interface, FAX interface, R-UIM interface, and indicator light interface. It is a 72-pin solder cup. As the TCPU board can be used in ETS1201 FWT, the interface meets the requirements of these two series products.

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1.2.2 Hardware Structure of the TUTUUSB

USB port Protection module

Primary power moduleFigure 1.3 Hardware structure of the TUTU board As shown in , the TUTU board consists of the user subsystem and the power and power management module part. The user subsystem consists of the SLIC interface module, SPI module, R-UIM card interface module, extended facsimile interface module, indicator light module, and environment variable monitoring module. The power and power management module part consists of the primary power interface protection module, primary power detection module, battery charging/discharging module, DC/DC power module, and the on/off control module. 1) The SLIC interface module receives and transmits the voice signals, sends the ringing tone and signal tone (such as dialing tone, busy tone, hooking prompt tone, and service prompt tone) to the common telephone set, sends the calling number to the common telephone set, and receives the dialed number. 2) 3) The SPI module realizes the conversion. The R_UIM card interface circuit serves as the interface for the communication4

ESD protection function and signal level


between the CPU system and the R_UIM card. It also supplies power to the R_UIM card and realizes the power protection function. 4) 5) 6) 7) 8) 9) The extended facsimile interface provides the control interface, simulated two wires, and asynchronous serial port required by the facsimile board. The indicator light module provides four RSSI indicators light, a dual-color batter indicator light, and a power indicator light. The environment variable monitoring module completes the board temperature detection, battery temperature sampling, and battery ID detection functions. The primary interface protection module completes the anti-static and overvoltage protection functions. The battery charging/discharging module completes the battery charging/discharging management function. The DC/DC power module completes the secondary conversion of DC power inside the board. It also provides the voltage stabilizing and constant current functions for the charging/discharging circuit. 10) The on/off control module controls the on and off of the external tact switch, startup of the primary power, and closedown of the software. Besides the above modules, there are also the interface components such as the connection solder cup between the TUTU and TCPU and USB connector.

1.3 Function Description of FWT Major Functional Modules1.3.1 User Interface SubsystemI. SLIC interface moduleThe SLIC interface module is located between the speech codec integrated in the QSC6020 chip and the terminal user. It constitutes the analog channel (except the G3 facsimile function) of the TUTU. This analog channel completes the following functions:

Receive and transmit the voice signals. Send the ringing tone and signal tone (such as dialing tone, busy tone, hooking prompt tone, and service prompt tone) to the common telephone set. Send the calling number to the common telephone set. Receive the dialed number.

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Figure 1.4 Structure of the TUTU In I, the part between the two dashed lines is the user interface module (TUTU) and the section enclosed by the dashed line is the SLIC interface module. The SLIC interface module consists of the SI3210 chip supplied by the Silicon Laboratory and some peripheral circuits. The chip can provide the SLIC, codec, DC-DC circuit, DualTone Multi-frequency (DTMF) detection, and other functions used to generate signals required by the analog phone. The following introduces the working process of the SLIC interface module: Transmit channel: The analog voice signal is sent from the telephone set to the RJ11 interface of the TUTU through the telephone line. The signal reaches the SI3210 and then is converted into the analog voice signal by the SLIC. After the sampling and coding of the codec, the signal is finally output as the standard PCM stream and sent to the PCM interface of the QSC6020. Receive channel: The voice data from the peer end is sent from the PCM interface of the QSC6020 to the codec of the SI3210 chip. The digital signal is converted to the analog voice signal by the codec and then demodulated by the SLIC onto the telephone line. Then the signal reaches the telephone set through the telephone line. The DTMF signal generated by keys on the telephone set is processed by the SLIC and codec and converted into the binary key values. Then the key values are reported to the QSC6020 through the SPI interface. The ringing tone, signal tone, service prompt tone, and calling number are generated and controlled by the QSC6020 module. The QSC6020 writes the parameters and commands into the codec through the SPI interface. Then the codec generates the corresponding signal and sends the signal to the telephone set through the SLIC. As the interface levels of the SLIC and QSC6020 are not consistent, the level conversion between the output signal of the SLIC and the input signal of QSC6020 is6


completed by the adaptation resistor. I shows the circuit used for level conversion between the SLIC output signal and QSC6020 input signal.

Figure 1.5 SLIC- QSC6020 interface level conversion circuit There are three types of interface between the SLIC and other units. They are the PCM stream interface, SPI interface, and the subscriber line audio interface connected with the external telephone set. 1) The PCM interface is the digital audio interface between the SLIC and the QSC6020. It transmits the telephone voice digital signal in the PCM format. This interface is implemented through the inter-board interface. Table 5.1 PCM interface between the SLIC and the QSC6020 PCM interface PCM_PCLK_A PCM_FSC_A PCM_DR_A PCM_DX_A SI3210 pin PCLK (3) FSYNC(6) DRX (4) DTX (5) Inter-board interface PCM_PCLK PCM_FSC PCM_DR PCM_DX Direction IN IN IN OUT QSC6020 pin GPIO_6 GPIO_3 GPIO_4 GPIO_5

Inside the SI3210, the internal clock signal of the SI3210 is generated through PLL by using the PLCK as the reference clock. The PCLK must be synchronous with the 8 kHz FSYNC. Available frequencies for the PCLK include 256 kHz, 512 kHz, 768 kHz, 1024 kHz, 1536 kHz, 2048 kHz, 4096 kHz, and 8192 kHz. The read/write timing diagram please reference the figure 8 in SI3210 datasheet.

2)

SPI interface allows the QSC6020 to configure the SI3210 parameters and collect information. This interface is implemented through the inter-board

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interface. Table 5.2 SPI interface between the SI3210 and the QSC6020 SPI interface SMI_CLK SMI_CS_N SMI_DIN SMI_DOUT SI3210 pin SCLK (38) CS (1) SDI (37) SDO (36) Inter-board interface SMI_CLK SMI_CS_N SMI_DIN SMI_DOUT Direction IN IN IN OUT QSC6020 pin GPIO_0 GPIO_36 GPIO_2 GPIO_1

The read/write timing diagram please reference the figure 7 in SI3210 datasheet.

II. Hold detect circuitTo reduce the power consumption in the standby mode, the SLIC is in the dormant state in the standby mode. At this time, if the user picks up the phone, the action cannot be detected. Thus, the external hold detect circuit is designed. In this way, when the SLIC chip is in the dormant state, the hold detect circuit can detect the offhook of the user and report it to the CPU so as to respond to the user. II shows the negative voltage circuit and II shows the hold detect circuit.

Figure 1.6 Negative voltage circuit

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Figure 1.7 Hold detect circuit

III. SPI moduleThe ETS1201FWTs provides the asynchronous serial interface or USB interface for control purpose.

1)

The USB transceiver is provided by QSC6020 on the TCPU board. The major functions of the TUTU are implemented by the USB circuits of the QSC6020 subsystem, including the ESD protection circuit.

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Figure 1.8 USB interface circuits

IV. R_UIM card interface circuitThe R_UIM card module consists of the R_UIM card power supply, connector, and ESD protection circuits. IV describes the signals of the interface between the R_UIM card interface module and other unit Table 8.1 Signal description of the R_UIM card interface module Signal VREG_PHONE R-UIM_RST R-UIM _CLK R-UIM _DAT R-UIM _EN Source or destination module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module Function description UIM card power supply UIM card reset signal UIM card clock signal UIM bidirectional signal UIM enable signal data

the implementation of the UIM card interface is shown as IV9. The diode provides the ESD protection for signals. The UIM card power is supplied by the LDO with the oneway output and the switch function. The seamless interface with the QSC6020 can be realized for the reset, clock, and data signals of the UIM card. The following figure shows the design:

Figure 1.9 UIM card circuit diagram

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The VDD_SIM power of the ETS1201 is provided by the power management chip on the TCPU board. The UIM card is directly powered through the R-UIM_EN, as shown in IV0.

Figure 1.10 ETS1200 VDD_SIM power

V. Extended facsimile interfaceThe extended facsimile interface provides interfaces for the extended facsimile board. These interfaces include the asynchronous serial interface and the PCM interface. The major function of the facsimile board is bidirectional conversation between the 64 kbps digital PCM stream and the facsimile data or signaling (such as the V.21 protocol). V describes the signals of the extended facsimile interface module: Table 10.1 Signal description of the extended facsimile interface and protection module Signal FAX_RD FAX _CTS_N FAX _RTS_N FAX _TD FAX_EN_N RING TIP VREG_ FAX Source or destination module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module SLIC module SLIC module DC/DC power module Direction IN IN OUT OUT IN IN IN IN Function description Serial port receiving Serial port clear to send Serial send port ready to

Serial port transmitting Facsimile enable signal Two-wire telephone line Two-wire telephone line 3.2 V main power

The extended facsimile interface module provides the control interface, simulated two wires and asynchronous serial port required by the facsimile board. V shows how these interfaces are implemented:

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Figure 1.11 Circuit of the extended facsimile interface module

VI. Indicator light moduleThe indicator light module provides four RSSI indicators light, a dual-color batter indicator light, and a power indicator light. It is driven by the QSC6020 on the TCPU board. VI describes the signals of the interface between the indicator light module and other units. Table 11.1 Signal description of the indicator light module Signal VERG_PHONE RSSI1 RSSI2 RSSI3 RSSI4 STAT1 STAT2 Source or destination module DC/DC power module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module Inter-board interface module Direction OUT IN IN IN IN IN IN Function description LED power Intensity indication Intensity indication Intensity indication Intensity indication Battery state indication Battery state indication

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Signal STAT3

Source or destination module Inter-board interface module

Direction IN

Function description External power state indication supply

VI2 shows the circuit of the indicator light module. The QSC6020 on the TCPU board provides the drive signal. The control signal of the indicator light is the positive logic, that is, the indicator light is on when there is high level.

Figure 1.12 Circuit of the indicator module

VII. Environment variable monitoring moduleThis module completes the board temperature detection and battery temperature sampling function.

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Table 12.1 Pin assignment of the environment variable monitoring module QSC6020 pin HKAIN0 HKAIN1 Function description Board temperature sampling Battery temperature sampling Signal TERMINAL_THERM BAT_TEMP

Board temperature detection is completed on the TCPU board. VII shows the battery temperature sampling circuit:

Thermal resistor

Figure 1.13 Battery temperature sampling circuit The battery temperature measurement range is between -10C and 55C.As shown in VII3, the thermal resistor is used. Within the above temperature range, the resistance variation range of the thermal resistor is between 282.1 k and 14.44 k. Thus, for the 10-bit ADC sample (1023 corresponds to 2.5 V. The accuracy of the sampling value is 0.0025 V), the corresponding values are respectively 813 and 124.

1.3.2 Power Supply and Power Supply Management SubsystemI. Primary Power Supply Interface Protection ModuleThe external power supply over-voltage protection module protects the input power supply. When the input voltage exceeds 30V, the resistance of the varistor RV301 turns to infinity. If the current is too high, the PTC automatic restore fuse RT501cut-off the power supply to protect the back circuit. See I4

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Figure 1.14 External power supply over-voltage protection module

II. DC/DC Power Supply ModuleThe DC/DC power supply provides the 4.4V main power for the whole system. Its maximum output current is 830 mA. The module mainly uses the PWM control chip (U501) and switching tube (Q501) to implement the secondary switching power supply circuit. The switching power supply can convert external power supply to 4.4 V. See II.

Figure 1.15 Power supply conversion circuit

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The PWM control chip adopts the TL494, including two differential amplifiers, one external adjustable oscillator, one pulse comparator, one time overflow controller, and one output control circuit. The differential amplifiers can operate ranging from -0.2V to VCC-0.2V. The time overflow controller has a fixed offset to ensure the stable output in case of external input changes. The external oscillator circuit can be set through Rt and Ct. In this design, Rt is set to 10k and Ct is set to 1000p, and the operating frequency is calculated as 100 kHz. The functional block diagram of TL494CN is shown II.

Figure 1.16 Functional block diagram of TL494

III. Power Supply Charging/Discharging ModuleThe battery charging and discharging module implements its function under the control of the QSC6020 of the TCPU board. Discharging function: When external power supply is unavailable, the QSC6020 controls the PM to turn on the battery switch and the battery starts to provide power supply. Charging function: When an external power supply is detected, the QSC6020 controls PM whether to charge the battery or not. III lists the interface signals between the battery charging/discharging module and other modules.

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Table 16.1 Description of signals of the battery charging/discharging module Signal name VREG_PHO NE V_BATT CHG_EN Source or destination module Secondary power supply conversion module Battery QSC6020 Function description Secondary power supply output 4.44V Battery output voltage QSC6020 output control

The circuit of the battery charging/discharging module is Shown as III. The charging of batteries is controlled by varying the output current of the secondary power supply. When the battery is charged in the quick mode, the grid of Q503 is low and without continuity. In this case, the internal differential amplifier of 494 controls the pulse duty ratio of PWM and maintains the output current of the switching power supply in 830mA. When the battery is charged in the slow mode, the grid of Q503 is high and it is turned on. The internal differential amplifier of 494 controls the pulse duty ratio of PWM and maintains the output current of the switching power supply in 55mA. Then the quick charging is stopped and the trickle charging starts. This feedback loop is realized by the operation amplifier 2 of TL494.

Figure 1.17 Charging circuit Because the battery in the circuit is directly connected with the 4.4V output of the secondary power supply, when the external power supply is not connected, the battery provides power supply for the system through the VREG_PHONE signal. So there is no special discharge control circuit.

IV. Secondary Power Supply Voltage-limiting ModuleThe secondary power supply voltage-limiting module limits the voltage of the secondary power supply to not exceeding 4.4V. After the constant current charging

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ends, the module stabilizes the secondary power supply output to 4.4V to provide power supply for the back circuit. This feedback loop is realized by the operation amplifier 1 of TL494. The circuit is shown in IV.

Figure 1.18 Secondary power supply voltage-limiting module

V. Power-on/Power-off ModuleThe S501 implements the power-on and power-off function. When the switch is set to ON, the TERM_ON generates the low-level switching on pulse and the SWITCH_ON generates the high-level switching on indication signal. The circuit is shown in V.

Power Switch

Figure 1.19 Switching ON/OFF module

1.3.3 QSC6020 SubsystemThe QSC6020 subsystem includes the voice coding/decoding unit, baseband signal

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processing unit, and the CPU system running for protocol software. All these functional units are integrated in the QSC6020 chip. The voice coding/decoding unit mainly implements the compression and coding of the 64K voice digital streams, for example EVRC codes, to make them suitable for the transmission in the wireless environment. The baseband signal processing unit mainly includes the baseband modulation/demodulation and channel coding/decoding functions. The subsystem also includes the FLASH for software storage and SRAM for software operation.

1.3.4 RF SubsystemFor ETS1201 FWT the frequency is 800MHz. Though the frequency bands are different, the structures of the boards are completely the same. Each unit of the FWT RF subsystem of ETS1201 is described below in detail.

I. Receive UnitFunctions of the receive unit: After the outband spurious of the RF signals received by the antenna of FWT is filtered by duplexer module, the signals are amplified by the RF low noise amplifier and filtered by the RF SAW and then are sent to the downconvert frequency mixer for frequency mixing. Because the RFR adopts the zero intermediate frequency structure, it can directly convert RF signals to baseband signals, and then implement I and Q demodulation, filter amplification, and ADC processing. The output digital baseband signals are then sent to the baseband processing circuit. The block diagram of the receive unit is shown in I0.

Figure 1.20 RF receive unit

II. Transmit UnitThe main function of the transmit unit is as follows: The transmit modulation module RFT directly amplifies the DA-converted analog I/Q signals and send to QSC6020. The RF signals are obtained after RF frequency mixing and RF filter frequency change. Then the RF signals are amplified by the RF power amplifier to the RF transmit signals with set output power. Finally, the outband spurious of the RF signals of FWT is filtered by duplexer module and the signals are then sent to the antenna. Another function of the duplexer module is to avoid the interference of transmission signals in the receiver. The block diagram of the transmit unit is as shown in II1.

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Figure 1.21 RF transmit unit

III. RF Frequency SynthesizerThe main function of the RF frequency synthesizer is to provide RF local oscillator signals for the transceiver. The duplexer interval of the RF is 45 MHz. So in the design, transmit and receive share the RF local oscillator. For both transmit and receive, the RF local oscillator is the high local oscillator. The signal frequency of the reference clock of the RF synthesizer is 19.2 MHz and the phase discrimination frequency is 25 kHz. The Rx PLL circuit is integrated in RFT, but the RX VCO and RX LO are still integrated in RFR. The block diagram of the RF synthesizer is shown in III2.

Figure 1.22 PLL circuit The RX-QP, RX-QM, RX-IM, and RX-IP are the outputs of the four baseband signals of RFR. The outputs are sent to MSM for processing. The SBST, SBCK, and SBDT are three control buses. The MSM controls the RFR by controlling these three signals. The TCXO signal provides the reference clock signal for all internal

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components. Three kinds of power supplies provide power for RFR: The VREGRFRX provides voltage for PM, VREG-TCXO provides voltage for the clock of RFR, and VREG-MSMP provides voltage for the internal components of RFR. The RF local oscillator signals provide the local oscillator signals needed by receive or transmit channels for RF down conversion or up conversion. Receive and transmit share one RF local oscillator signal.

1.4 Parameter Index1.4.1 Primary indices of the receiving unit:(1) Basic indices (2) Frequency range: Work frequency 869MHZ--894MHZ MHz (3) Noise coefficient under sensitivity condition:

ETS1201 Series Fixed Wireless Terminal Maintenance Manual

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