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* UHF
FFSK radio data transmission
* Transparent 1200 - 9600 bps radio
data transmission
* Optional RS-232, RS-485, TTY serial
interface
* 4 x 640 bytes data buffer
* Error Detection (16 bit CRC)
* Forward Error Correction (FEC)
* Stored configuration (EEPROM)
* LED indicators for radio and serial
functions
* Test functions |
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Brief Description
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The ARTHUR Series of Wireless Data Modems is
a range of UHF FFSK modem with se-rial data interface. Models
currently available are as follows:
ARTHUR-312 1200/2400 bps radio data transmission speed.
(CRC)
ARTHUR-349 4800/9600 bps radio
data transmission speed. (CRC, FEC)
The ARTHUR provides half-duplex, fully transparent operation
regardless of the serial data protocol. Over-air speeds up to
9600 bps are achievable and serial data can be input at various
baud rates up to 28800 bps.
The modems have User ID, and can have station address. All ARTHUR
modems within a system must have the same User ID. If the modem
has station address, then only those re-ceived blocks are output
to the serial port that have the proper address.
Access to all configurable parameter is possible in test mode
through the serial line. The configurable parameters are as
follows:
* Station address (disabled, or
0-254)
* Serial communication:
* Baud rate (1200, 2400, 4800,
9600, 14400, 19200, 28800 bps)
* Word length (7, 8 bits)
* Parity (disabled, even, odd)
* Flow control (disabled, RTS)
* Block recognition (Starting and
Terminating character, time-out)
* Timed serial reception
* Error checking
* Radio communication:
* Transmission switch-on time
* Transmission switch-off time
Applications include Alarm Systems, Data Acquisition, remote
Metering, Remote Control systems, SCADA, Security Systems, Telemetry,
Traffic Information and Control systems, etc. |
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Primary Mode
of Operation
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Generally the modem is in receiving mode, both on radio and
serial port. Depending on which port starts a new block, the
modem will act as a receiver or as a transmitter. The modem
is half-duplex, so if a communication has already started in
one direction, then an other communication started from the
other direction will be lost.
Reception
1. When a block, containing an
appropriate header block and valid CRC, is received on the radio,
then the number of bytes specified in the header block will
be written into the ra-dio reception data buffer.
2. If the received block is corrupt (CRC invalid) and
the error checking is enabled, then the modem ignores the received
block, and waits for the next block.
3. If the header block is invalid, then the modem ignores
the received block, even if the er-ror checking is disabled.
4. The header block contains the User ID. If it is not
the same as the User ID of the re-ceiving modem, then the modem
ignores the received block.
5. If the modem has a station address, then the first
byte of the data block (the received block without the header
block) is the address. If it is not the same as the station
address of the modem, then the modem ignores the received block.
6. The modem waits for the end of the previous serial
transmission. If during this time a new block is arriving, then
it will be lost.
7. The modem copies the data from the radio reception
data buffer to the serial transmis-sion data buffer, starts
the serial transmission and the modem can receive the next block
from the radio.
8. The modem output the contents of the serial transmission
data buffer to the serial port in the format specified its configuration.
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Transmission
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1. The modem receives a block
on the serial port to the serial reception data buffer. If the
starting character is enabled, then all the characters received
before the starting character is ignored and the reception of
the starting character starts the new block. Else the first
received byte starts the new block. The starting character is
not transmitted on the radio (See the "Configuration" section).
2. If the received block is corrupted (parity or framing
error), and the error checking is en-abled, then the received
block is ignored, no radio transmission is performed.
3. If the terminating character is enabled, then the
reception of the terminating character means the end of the
serial reception. Else 20 ms time-out after the last character
recep-tion means the end of the block. The terminating character
is not transmitted on the ra-dio.
4. If the size of the received block reaches the 640
bytes, the modem stops the reception. If the flow control is
enabled, then the modem inactivates its RTS line to suspend
the transmission of the attached device. If the terminating
character is disabled and the flow control is enabled, then
the received block is correct. Else the received block is corrupt,
and if the error checking is enabled, then the modem ignores
the received block.
5. The modem waits the end of the previous radio transmission.
During this time the mo-dem can not receive a new block on its
serial port. If the flow control is enabled, then during this
time the RTS line is inactive.
6. The modem copies the contents of the serial reception
data buffer to the radio transmis-sion data buffer, switch on
the radio transmitter, and wait for the next reception on the
serial port.
7. After the configured switch-on time the modem transmits
the contents of the radio transmission data buffer, with a proper
header block. |
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Test Mode
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In test mode can be the modem tested and configured. To put
the modem to test mode do as follows:
1. There is a push-button behind
a small hole on the bottom edge of the modem. Push this button
with a pointed tool. (The power must be on.)
2. The quicker blinking of the
Run LED indicates the test mode.
3. Release the button. In test
mode the serial data format is: 9600,8,N,1.
The format of the command and answer block is:
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#
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Command
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Parameters
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CR (0Dh)
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1 byte
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1 byte
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n * 2 bytes
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1 byte
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The parameters are in hexadecimal ASCII format, the most significant
byte first. For ex-ample, when a parameter value of 19 (13h)
is to be set, then a '1' and a '3' character should be sent.
All parameters must be sent on two bytes, that is a decimal
10 (0Ah) should be sent as a '0' and an 'A' character.
In the answer the command byte is repeated, or in case of invalid
command an 'E' character means an error answer.
LED test
| Command: |
L |
| Parameter: |
- |
| Return parameter: |
Expected state of LEDs (1 - ON, 0 - OFF), or 'Esc' (1Bh)
at the end of test. |
The modem set all the LEDs (Run, SerTr, SerRec, RadTr, RadRec,
RadCdt), than changes the state of them in every one second.
At every change, the modem sends an answer con-taining the expected
state of LEDs.
The modem continues the test until receives an 'Esc' character,
than switches off all the LEDs, and sends an answer containing
an 'Esc' parameter. |
| RAM test |
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| Command: |
X |
| Parameter: |
- |
| Return parameter: |
The first defective RAM address (two bytes), or -1 (FFFFh)
if the RAM is correct. |
| EEPROM checksum
test |
| Command: |
C |
| Parameter: |
- |
| Return parameter: |
1 if the checksum is valid, 0 if invalid. |
| Radio transmission
test, fixed byte |
| Command: |
T |
| Parameter: |
The byte to be transmitted. |
| Return parameter: |
The transmitted byte, or 'Esc' at the end of test. |
| The modem continuously transmits the chosen byte, until the
reception of an 'Esc' character. |
| Radio transmission
test, random byte |
| Command: |
N |
| Parameter: |
- |
| Return parameter: |
-, or 'Esc' at the end of test. |
| The modem continuously transmits pseudo-random bytes, until
the reception of an 'Esc' character. |
| Radio transmission test,
Rx EYE |
| Command: |
A |
| Parameter: |
- |
| Return parameter: |
-, or 'Esc' at the end of test. |
This is a special test for the modem chip, to examine the
radio channel. Reception of an 'Esc' character stops the test.
This test is available only for the ARTHUR-349. |
| Read configuration
Return |
| Command: |
R |
| Parameter: |
- |
| parameters: |
1. Number of the configuration bytes.
2. Configuration bytes. |
| The modem sends the number of configuration byte and the current
values of them. The meanings of the configuration bytes are
in the section "Configuration". |
| Command: |
B |
| Parameter: |
The index of the configuration byte. |
| Return parameters: |
1. The index of the configuration byte.
2. The current value. |
| Command: |
W |
| Parameters: |
1. Number of the configuration bytes.
2. Configuration bytes. |
| Return parameter: |
Number of the written configuration bytes. |
| The modem stores the given configuration bytes. The modem
does not check the values, but in a few cases may ignore some
of them in the normal operation (See the "Configura-tion" section).
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| Command: |
Y |
| Parameters: |
1. The index of the configuration byte.
2. The new value. |
| Return parameters: |
1. The index of the configuration byte.
2. The stored value. |
| Read version informationReturn
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| Command: |
V |
| Parameter: |
- |
| parameters: |
1. Type number.
2. Lower baud rate on radio (1 - 1200, 4 - 4800).
3. Higher baud rate on radio (2 - 2400, 9 - 9600).
4. Version number 1 (1.20).
5. Version number 2 (1.20).
6. Version number 3 (1.20).
7. Date of last modification - year.
8. Date of last modification - month.
9. Date of last modification - day.
10. Date of last modification - hour.
11. Date of last modification - minute. |
| Command: |
Q |
| Parameter: |
- |
| Return parameter: |
- |
| The modem returns to normal mode. The slower blinking of the
RUN LED indicates the normal mode. |
| Command: |
E |
| Parameters: |
1. Error code.
2. Error parameter. |
| If the modem receives an invalid or corrupted command, or
if it can not execute the given task, then it sends an error
answer. The possible error codes are: |
| Invalid command |
Error code: 1. Invalid command byte was received. The error
parameter contains the invalid command byte. |
| Invalid parameter |
Error code: 2. Not a hexadecimal ASCII parameter was re-ceived.
The error parameter is 0. |
| EEPROM defective |
Error code: 4. The modem can not write the EEPROM (to store
the configuration bytes). The error parameter contains the defec-tive
EEPROM address. |
The ARTHUR has several configurable parameters, so the modem
can be adjusted to wide range of applications.
The modem provides fully transparent data transmission over-air,
regardless of the used se-rial data protocol, so different equipment
can incorporate within a complex system. |
| Station
address enable |
| Index: |
0 (00h) |
Any nonzero value means that the modem has station address,
the value stored in the Sta-tion Address parameter.
If the modem has no station address, then all the received data
blocks are output to the seri-al port.
If the modem has station address, then the first byte of the
data block must be the destina-tion address. If the destination
address is the station address of the modem, then the re-ceived
data is output to the serial port, without the destination address.
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| Station
address |
| Index: |
1 (01h) |
If the station address is enabled, then the value of this parameter
is the station address. The station address must be in the 0
- 254 range.
The station address 255 is for broadcast messages, that all
the modems receive and output to the serial port. The devices
attached to the modems must not answer to a broadcast message.
At the sender side, the application using the modem, should
insert the destination address to the beginning of the message.
At the receiving side the modem strips the destination ad-dress
from the data block. |
| Index: |
2 (02h) |
The available values: |
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Value
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Baud Rate
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0
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1200 bps
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1
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2400 bps
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2
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4800 bps
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3
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9600
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4
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14400
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5
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19200
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6
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28800 bps
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| Any other value means the default 9600 bps. |
Serial word length |
| Index: |
3 (03h) |
The available values: |
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Value
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Word length
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0
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7 bits
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1
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8 bits
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Any other value means the default 8 bits word length.
The 7 bits word length is only available with enabled parity.
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| Serial
parity |
| Index: |
4 (04h) |
The available values: |
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Value
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Parity
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0
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No parity (N)
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1
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Odd parity (O)
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2
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Even parity (E)
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Any other value means the default even parity.
If 7 bits word length and no parity are set, then the modem
forces the even parity. |
| Serial flow
control |
| Index: |
5 (05h) |
Any nonzero value enables the flow control.
If the flow control is disabled and the serial reception overflows,
then the received block is corrupted, and the modem does not
transmit it on the radio (in case of enabled error checking).
If the flow control is enabled, then the modem has to be able
to suspend the transmission of the attached device by inactivating
its RTS line. The attached device can not stop the transmission
of the modem, because the over-air reception can not be stopped.
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| Serial starting
character enable |
| Index: |
6 (06h) |
A value of 0 disables the starting character. Any other value
enables the starting character, which is stored in the Starting
Character parameter.
If the starting character is disabled, then the first received
byte means the start of a new block. If the starting character
is enabled, then the reception of the starting character means
the start of a new block.
Any character before the starting character is ignored. The
starting character is not transmitted on the radio. |
| Serial
starting character |
| Index: |
7 (07h) |
If the starting character is enabled, then the value of this
parameter is the starting character. |
| Serial terminating
character enable |
| Index: |
8 (08h) |
A value of 0 disables the terminating character. Any other value
enables the terminating character, which is stored in the Terminating
Character parameter.
If the terminating character is disabled, then a 20 ms time-out
after the last received byte means the end of the serial reception.
If the terminating character is enabled, then the reception
of the terminating character means the end of the serial reception.
The terminating character is not transmitted on the radio.
Because the first byte of the block can be a destination address,
every block must contain minimum one character, and the first
byte is never be concerned as terminating character. |
| Serial terminating
character |
| Index: |
9 (09h) |
If the terminating character is enabled, then the value of this
parameter is the terminating character. |
| Timed serial
reception enable |
| Index: |
11 (0Bh) |
Any nonzero value enables the timed serial reception. If the
timed serial reception is enabled, then after starting a new
serial reception there must not be more than 20 ms between two
bytes. If there is a longer time between two bytes, then the
reception is finished, and if the terminating character is enabled,
then the block is invalid. |
| Error checking
enable |
| Index: |
12 (0Ch) |
Any nonzero value enables the error checking.
If the error checking is enabled, then only the error free blocks
are output to the serial port. |
| Radio transmitter
switch-on time |
| Index: |
13 (0Dh) |
Once the radio is switched to transmit there will be a short
delay while the synthesiser locks and the transmitter reaches
operating power. This time can be set here.
The switch-on time can be set in 10 ms units, that is a value
of 10 means 100 ms. The smallest acceptable value is 10 ms (1),
the biggest is 2.55 seconds (255). If 0 is set, then the modem
uses 10 ms switch-on time. |
| Radio transmitter
switch-off time |
| Index: |
14 (0Eh) |
The amount of time, set in this parameter, will be applied after
the last byte sent, before the transmitter is switched off.
The switch-off time can be set in 10 ms units. |
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Radio
Settings
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ARTHUR-312
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HF input/output levels
The HF output level can be adjusted, using the P201 potenciometer.
The output level can be measured between the M202 (GND*) and
M201 (TXA*) measuring pins. The most ra-dio equipments need
400mVpp.
The HF input level can be adjusted, using the P202 potenciometer.
The imput level can be measured between the M205 (GND) and M204
(RXA) pins. The value of 650 mVpp gives the best Bit Error Ratio.
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Switch to transmit
The most radio has an input pin (PTT), that should be pulled
down to GND to switch the transmitter (ie.: MOTOROLA GM300 ).
Using such radio equipment, the 2-3 pins of the V201 jumper
should be shortened.
Some radio has no PTT input (ie.: YAESU FTH-7010) In this case,
the microphone input should be pulled down to GND. Using such
radio, the 1-2 pins of the V201 jumper should be shortened.
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Data transmission speed
The over-air data transmission speed can be 1200 or 2400 bps.
Use the V203 jumper to select the transmission speed. The opened
jumper selects the 1200 bps, the shortened jum-per selects the
2400 bps.
For the higher transmission speed a better radio equipment should
be used (ie.: MOTOROLA GM300). |
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Specifications
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Mechanical & Environmental |
| Size: |
140 x 80 x 25 mm |
| Weight: |
340 grams |
| Operating temperature: |
0°C - 70°C |
| Power
Supply |
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| Power Supply: |
8V - 15V DC (12V - 28V DC optional) |
| Supply Current: |
100 mA (12V) |
| Serial Connector
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| The serial port of the modem is a 9-Way 'D' type male connector.
In case of the default RS-232C (DTE) type connection the connections
are as follows: |
Pin 1 |
not used |
| Pin 2 |
RxD (Receive Data) |
| Pin 3 |
TxD (Transmit Data) |
| Pin 4 |
not used |
| Pin 5 |
GND (Ground) |
| Pin 6 |
not used |
| Pin 7 |
RTS (Request To Send) |
| Pin 8 |
CTS (Clear To Send) |
| Pin 9 |
not used |
Optionally the modem can be delivered with decoupled RS-232C,
RS-485, decoupled RS-485, passive current loop (TTY). |
Radio Connector
The radio port of the modem is a 9-Way 'D' type female connector.
Connections are as follows: |
| Pin 1 |
Power Supply for the radio (optional) |
| Pin 2 |
TXA HF output (120 mVrms) |
| Pin 3 |
RXA HF input (775 mVrms) |
| Pin 4 |
not used |
| Pin 5 |
GND (Ground) |
| Pin |
6 not used |
| Pin 7 |
PTT radio switch to transmit (GND) |
| Pin 8 |
not used |
| Pin 9 |
not used |
| The HF output and HF input levels can be adjusted in the modem.
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| LED Indicators
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| Power |
Power is on. |
| Run |
In normal mode it changes its state three times in a second,
in test mode it changes seven times. |
| SerTr |
Serial transmission. |
| SerRec |
Serial reception. |
| RadTr |
Radio transmission. |
| RadRec |
Radio reception.It is switched on only after receiving a
valid header block. |
| RadCdt |
Radio carrier detect. |
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