kopia lustrzana https://github.com/SP8EBC/ParaTNC
209 wiersze
9.2 KiB
Plaintext
209 wiersze
9.2 KiB
Plaintext
This documentation covers few different hardware revisions. Each secion which is
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specific to certain Hw Rev is marked by a letter.
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If section or point is universal across all revision it doesn't have any explicit
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marking.
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1. INTRODUCTION
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ParaTNC is not only a software which runs on the STM32VLDISCOVERY board. Let's
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be honest, using evaluation boards is not very professional and may lead to
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great mess with soldering, poor-quality universal PCBs and then short
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circuits, noise etc. This is why the ParaTNC hardware was designed to have
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everything on single PCB without a lot of jumper wires across.
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The ParaTNC as a software is universal and it might by used both on ParaTNC
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hardware and still on STM32VLDISCOVERY board with everything else connected
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to it using kynar wire.
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2. KEY FEATURES
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There were few key assumptions during the designing process which came from
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long experience with many different stations
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-> Ground Isolation between the controller and the radio.
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-> Ground Isolation and isolated power supply for external meteo sensors.
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-> RS232 and optional RS485 transceivers on board.
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-> Internal connectors for breakout board with MS5611 pressure sensor.
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-> Separate watchdog IC.
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-> Optional Radiometrix BiM1H 500mW VHF transceiver tuned on 144.800MHz.
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-> The PCB mechanical design which fits into standard Mikrotik RB411 case.
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-> Supplied from single +12V...14V5 DC source using standard DC barrel jack.
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The main problem observed during long experience with meteo stations is RF
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feedback. Most sensors (like temperature, wind and humidity) needs to be
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placed outside to ensure proper measuremenets quality. Unfortunately
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extending micro GPIO pins directly by using long cables placed along with
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the RF coax cabling, definitely allows the RF energy from stations own TX
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to get inside the micro and do a lot of mess. In less dangerous case this
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may end with distorted AF coming into modulator input, in the worst case
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the micro could just hang with PTT engaged.
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3. SERIAL BOOTLOADER
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The PCB has a JTAG pinout exposed which may be used for downloading the
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software into micro. If User don't want to use a JTAG programmer or he
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just doesn't own one, the serial bootloader may be used.
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The bootloader is activated by shorting the proper jumper and reseting
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the controler. Then the application provided by STMicroelectronics
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could be used to download the HEX file into the micro.
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4. CONNECTORS PINOUT (BACK EDGE) - HW-RevA
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-------------------------------------------------------------------------------
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|RS485B , RS485A| |+5Vsw, OneWire, AGND| |TX20, AGND, +5Vsw, DTR| \r\n
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|+12V, +5V, +5Vi, +3V3, AGND, GND|
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Where:
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RS485A and RS485B -> RS485 bus, protected by TVS (Clamping diodes)
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OneWire -> Isolated one wire bus
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TX20 -> Isolated data bus from LaCrosse TX20 anemometer
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DTR -> Enable pin for TX20 anemometer. Permamently pulled down do AGND
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+5Vi -> Isolated +5V generated by internal DC-DC converter
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+5Vsw -> Switched and Isolated +5V. This line could be power cycled by
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the micro if no communication will be received from either the
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anemometer or one wire thermometer
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+3V3 -> Main uC supply voltage regulated internally by LDO
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+12V -> Main supply voltage, hooked in paralel to DC jack
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AGND -> Analog GND for radio and sensors
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GND -> Main ParaTNC common with DC jack
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4. CONNECTORS PINOUT (BACK EDGE) - HW-RevB
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-------------------------------------------------------------------------------
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|RS485B , RS485A| |+12V, AGND, +5Vi, +5Vsw, +5V, GND| |+5Vsw, OneWire, AGND|
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|AGND, TX20-SPD, DIRECTION, +5Vsw|
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Where:
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RS485A and RS485B -> RS485 bus, protected by TVS (Clamping diodes)
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OneWire -> Isolated one wire bus
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TX20-SPD -> Isolated data bus from LaCrosse TX20 anemometer or
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an windspeed input (pulse out) from mechanical anemometer
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DIRECTION -> Wind direction input (pot wiper) from mechanical anemometer
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DTR -> Enable pin for TX20 anemometer. Permamently pulled down do AGND
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+5Vi -> Isolated +5V generated by internal DC-DC converter
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+5Vsw -> Switched and Isolated +5V. This line could be power cycled by
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the micro if no communication will be received from either the
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anemometer or one wire thermometer
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+12V -> Main supply voltage, hooked in paralel to DC jack
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AGND -> Analog GND for radio and sensors
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GND -> Main ParaTNC common with DC jack
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4. CONNECTORS PINOUT (BACK EDGE) - HW-RevC
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-------------------------------------------------------------------------------
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|+12V, AGND, +5Vi, +5sw, OC-OUT, GND| |RS485B , RS485A| |+5Vsw, OneWire, AGND|
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|AGND, TX20-SPD, DIRECTION, +5Vsw|
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Where:
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RS485A and RS485B -> RS485 bus, protected by TVS (Clamping diodes)
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OneWire -> Isolated one wire bus
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TX20-SPD -> Isolated data bus from LaCrosse TX20 anemometer or
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an windspeed input (pulse out) from mechanical anemometer
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DIRECTION -> Wind direction input (pot wiper) from mechanical anemometer
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+5Vi -> Isolated +5V generated by internal DC-DC converter
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+5Vsw -> Switched and Isolated +5V. This line could be power cycled by
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the micro if no communication will be received from either the
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anemometer or one wire thermometer
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OC-OUT -> Additional isolated open-collector output
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+12V -> Main supply voltage, hooked in paralel to DC jack
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AGND -> Analog GND for sensors (BUT NOT RADIO!!)
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GND -> Main ParaTNC common with DC jack
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5. RJ45 (RS232) pinout
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The RJ45 jack on the front of the PCB is NOT THE ETHERNET! Please don't plug
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any twisted pair Ethernet cable onto it.
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The RJ45 socket is just an RS232 connector in standard Cisco Serial Console
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pinout. The proper RJ45 -> DB9 cable could be very easly obtain on any
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online shop like eBay etc. The only difference between official Cisco pinout
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and ParaTNC is an optional (disabled by default) +5V voltage which may by
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applied to pin 7 of RJ45 connector, which is wired to pin 4 of female DB9 plug.
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6. Female DB9 (radio) pinout
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The DB9 connector is used to connect to the radio used for receiving & txing
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data on the APRS radio network. As mentioned before this connector has a ground
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separation and it is isolated from the microcontroller using AF transformer and
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optocoupler (for PTT). An input transformer has a 220uF 16V electrolytic
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capaciter in series between a primary winding and DB9. The positve lead faces
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the DB9 connector to isolate potential DC offset coming from the radio.
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The connector itself repeats the Tapr (Muel) TNC-2 pinout which goes as below:
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Pin 3 - AF from Radio to TNC
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Pin 4 - Open Drain PTT
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Pin 5 - AF from TNC to Radio
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Pin 7 - AGND
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7. Adjusting audio levels
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The ParaTNC controller has two trimpots mounted on PCB which may be used to
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tune the level of audio coming from/to the radio.
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The trimpot located close to the microcontroller is used to set the output signal
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level. The another one which is near right isolation transformer changes the
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input level and it is hooked up between the primary winding and DC-blocking
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electrolytic
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8. JUMPERS (Sketch not to scale!)
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-------------------------------------------------------------------------------
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| JP1 MS5611 sensor |
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| x ----------- x |
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| x |JTAG conn| x |
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| ----------- x |
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| x |
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| /----------\ x |
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| | | x |
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| | MICRO | DHT22 sensor x |
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| | | x |
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| \----------/ x |
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| x |
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| RS232 sel |
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| >xx< |
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| >xx< |
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| JP3 |
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| x |
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| x -------------- |
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| | RS232 conn | |
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| -------------- |
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-------------------------------------------------------------------------------
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JP1 - This is used to jump to the serial bootloader during startup
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JP3 - This is used to apply regulated +5V supply to RS232 connector
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RS232sel - This pair of jumpers is used to choose RS232, present only in HW-RevA
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MS5611 - .1' Connector for GY-63 breakout board with MS5611 pressure sensor
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=========
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| empty |
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| empty |
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| empty |
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| SDA |
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| SCL |
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| GND |
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| +5V |
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=========
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DHT22 - .1' connector for DHT22 humidity sensor
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==========
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| +5V |
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| Sensor |
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| GND |
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==========
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9. CHOOSING BETWEEN RS485 AND RS232 (applies only to HW Revision A)
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ParaTNC controller has connectors for both 485 and 232 variant of RS standard.
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This doesn't automatically means that ParaTNC has two separate serial ports,
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this is still the same serial port from the microcontroller which just may
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be converted differently. Due to how TTL and CMOS logic works You CANNOT use
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both 232 and 485 at once. If You'll leave 485 and 232 enabled at once the main
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logic supply voltage may be shorted to ground if one transceiver will receive
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logic one while the another will receive zero (and pull low the TTL/CMOS rx
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line which goes to the micro)
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It is strongly recommended to put MAX485 into socket. In such case the
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transition from RS485 to RS232 could be done just by removing MAX485
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from the socket and then shorting the RS232sel jumpers block. Jumpers
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needs to be shorted horizontally
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