 |
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The
RX2M receiver and TX2M transmitter modules offer a low
power, reliable data link in an industry-standard pin
out and footprint. This makes the TX2M/RX2M pair ideally
suited to those low power applications where existing
wideband modules have insufficient range, or where multi-channel
operation is needed.
Two versions are available, covering the 458.5-459.1MHz
UK band (at 100mW) and the European 433.05-434.79MHz band. |
 |
|
|
-
433MHz
version conforms to EN 300 220-3 and EN 301 489-3
and 458MHz version to MPT 1329 (UK specs)
- Any custom band between 420MHz
and 480MHz with 5MHz (AR0) frequency range
-
High
performance double superhet, 128 channel PLL synthesizer
with TCXO
-
Data
rates up to 5 kbps for standard module
-
Usable
range over 1km
-
Fully
screened. Low profile
-
Feature-rich
interface (RSSI, noise squelch, analogue and digital
baseband)
- Incorporate a 1200baud dumb modem
-
Re-programmable
via RS232 interface
-
Low
power requirements
|
-
Handheld
terminals
-
EPOS
equipment, barcode scanners
-
Data
loggers
-
Industrial
telemetry and telecommand
-
In-building
environmental monitoring and control
-
High-end
security and fire alarms
-
Vehicle
data up/download
|
Technical
Summary
- Size:
59 x 38 x 7mm
- Operating
frequency: 458.5-459.1MHz or 433.05-434.79MHz
- 23 channels
in 458MHz band (128 channels max.)
- Transmit
power: +20dBm (100mW) nominal
- Supply
range: 4.5V - 16V
- Current
consumption: 100mA transmit, 13mA receive
- Data bit
rate: 5kbps max. (standard module)
- Receiver
sensitivity: -118dBm (for 12dB SINAD)
|
| Evaluation Platform:
Narrow
Band Evaluation Kit |
| |
|
 |
Figure 1: TX2M block diagram |
|
Figure 2: RX2M block diagram |
|
Figure 3: TX2M
Footprint (Top of the unit) view
|
| |
| Pin
Description - TX2M |
| |
| Pin |
Name |
Function |
| Power: A |
| 1 |
Vcc |
+4.5V to 16V supply |
| 2 |
Gnd |
Ground |
|
|
|
|
| RF: B |
| 1 |
Gnd |
RF ground |
| 2 |
RF out |
To antenna |
| 3 |
Gnd |
RF ground |
| |
|
|
| User: C |
| 1 |
0V |
Ground |
| 2 |
TXE |
Transmitter enable. Low
= ON, open = off. 4k7 pullup to raw Vcc |
| 3 |
TXD |
DC coupled input for 3-12V
CMOS logic. Leave open if unused |
| 4 |
AF in |
AC coupled 1V pk-pk +/-
10% Analogue input |
| 5 |
+4.4Vout |
DC supply. 75mA max. drain.
Only present when TXE is
low |
| 6 |
PGM |
Serial programming/configuration
input at RS232 level |
| 7 |
0V |
Ground |
| 8 |
P1 (mod TXD) |
Parallel
frequency select inputs. Inverted logic, 10k pullups to
4V |
| 9 |
P2 (mod NC) |
| 10 |
P3 (mod TXH) |
|
|
Figure 4: RX2M
Footprint (Top of the unit) view
|
| |
| Pin
Description - RX2M |
| |
|
Pin
|
Name
|
Function
|
| Power: A |
| 1 |
Vcc |
+4.5V to 16V supply |
| 2 |
Gnd |
Ground |
| |
|
|
| RF: B |
| 1 |
Gnd |
RF ground |
| 2 |
RF in |
To antenna |
| 3 |
Gnd |
RF ground |
| |
|
|
| User: C |
| 1 |
RSSI |
DC level between 0.5V
and 2.5V. 60dB dynamic range |
| 2 |
SQF |
Noise operated carrier
detect. Open collector. ON/low = no signal |
| 3 |
AF out |
200mV pk-pk audio. DC
coupled, approx 1V bias. Muted by squelch |
| 4 |
RXD |
Open collector output
of data slicer. Need external pull-up |
| 5 |
+4.4V out |
DC supply. 75mA max. drain.
Present if unit is powered |
| 6 |
0V |
Ground |
| 7 |
PGM |
Serial programming/configuration
input at RS232 level |
| 8 |
P1 (mod NC) |
Parallel frequency
select inputs. Inverted logic, 10k pullups to 4V |
| 9 |
P2 (mod RXD) |
| 10 |
P3 (mod CDE) |
|
Note:
1. Internal AF Input gain is factory set for 1Vpk-pk to produce
3kHz peak deviation and minimum distortion. Analogue gain may
be set for an input level of 50mV - 2V pk-pk. This cannot be
done without appropriate test equipment. Contact factory for
details
2. Carrier detect on RX2M mutes the AF and DATA outputs when
RF input signal is <-123dBm. This can be factory disabled
if required.
3. There are no pullups on the open collector outputs. External
pull-up resistor should be used.
4. With 1200baud modem mode enabled, parallel selection of channel
is unavailable as the P1-P3 lines are used for input/output
operations. |
|
|
TX2M and RX2M serial
interface commands
2400 baud RS232. 8 bit data, no parity,
1 start bit, 1 or 2 stop bits, No flow control.
Transmit (pin 3 on DB9) and Signal Ground (pin 5 on DB9) should
be connected to PGM and 0V pin.
| SINGLE nnnnn |
set value of N for single
channel operation |
| GOCHAN xx
|
serial select
of channel xx (0 to 127) |
| LOADMX xx |
set highest permitted
(serial selected) channel xx (others default to ch0) |
| LOAD aa nnnnn |
set value of N for channel
aa (channels 0 to 15) |
| LOADTB nnnnn |
set value of
N for channel 16 (channels 17 to 127 then in sequence) |
| RVALUE rrrr |
enter value for R register |
| SETPAR |
channel selected by 3
bit parallel input (0 to 7). Disable modem |
| SETSER |
channel selected by most
recent 'gochan' operation |
| SETMOD |
enable internal modem.
Frequency selected by most recent 'GOCHAN' or 'SINGLE' |
| GOTEST |
250Hz test tone transmission |
| <CR> |
process entry (Carriage
Return = 0D hex ) |
| / |
clear all buffers |
xx = a channel number from 00 to 127
aa = a two digit channel number from 00 to 15
nnnnn = a synthesizer N register value, (up to 65535)
rrrr = the synthesizer R register value, (up to 16383)
|
|
|
| Channel
number |
433MHz
band |
N
value for TX |
N
value for RX |
458MHz
band |
N
value for TX |
N
value for RX |
|
0
|
433.050 |
/LOAD00
17322 |
/LOAD00
16466 |
458.525 |
/LOAD00
18341 |
/LOAD00
17485 |
|
1
|
433.075 |
/LOAD01
17323 |
/LOAD01
16467 |
458.550 |
/LOAD01
18342 |
/LOAD01
17486 |
|
2
|
433.100 |
/LOAD02 17324 |
/LOAD02 16468 |
458.575 |
/LOAD02 18343 |
/LOAD02 17487 |
|
3
|
433.125 |
/LOAD03 17325 |
/LOAD03 16469 |
458.600 |
/LOAD03 18344 |
/LOAD03 17488 |
|
4
|
433.150 |
/LOAD04
17326 |
/LOAD04
16470 |
458.625 |
/LOAD04
18345 |
/LOAD04
17489 |
|
5
|
733.175 |
/LOAD05 17327 |
/LOAD05 16471 |
458.650 |
/LOAD05 18346 |
/LOAD05 17490 |
|
6
|
433.200 |
/LOAD06
17328 |
/LOAD06
16472 |
458.675 |
/LOAD06
18347 |
/LOAD06
17491 |
|
7
|
433.225 |
/LOAD07 17329 |
/LOAD07 16473 |
458.700 |
/LOAD07 18348 |
/LOAD07 17492 |
|
8
|
433.250 |
/LOAD08 17330 |
/LOAD08 16474 |
458.725 |
/LOAD08 18349 |
/LOAD08 17493 |
|
9
|
433.275 |
/LOAD09
17331 |
/LOAD09
16475 |
458.750 |
/LOAD09
18350 |
/LOAD09
17494 |
|
10
|
433.300 |
/LOAD10 17332 |
/LOAD10 16476 |
458.775 |
/LOAD10 18351 |
/LOAD10 17495 |
|
11
|
433.325 |
/LOAD11 17333 |
/LOAD11 16477 |
458.800 |
/LOAD11 18352 |
/LOAD11 17496 |
|
12
|
433.350 |
/LOAD12 17334 |
/LOAD12 16478 |
458.825 |
/LOAD12 18353 |
/LOAD12 17497 |
|
13
|
433.375 |
/LOAD13
17335 |
/LOAD13
16479 |
458.850 |
/LOAD13
18354 |
/LOAD13
17498 |
|
14
|
433.400 |
/LOAD14 17336 |
/LOAD14 16480 |
458.875 |
/LOAD14 18355 |
/LOAD14 17499 |
|
15
|
433.425 |
/LOAD15 17337 |
/LOAD15 16481 |
458.900 |
/LOAD15 18356 |
/LOAD15 17500 |
|
16
|
433.450 |
/LOADTB 17338 |
/LOADTB 16482 |
458.925 |
/LOADTB 18357 |
/LOADTB 17501 |
|
F max
|
434.775 |
/LOADMX 69 |
/LOADMX 69 |
459.100 |
/LOADMX 23 |
/LOADMX 23 |
|
| |
|
Please observe the following ERC/REC 70-03 (April 2004) Annex
1 recommendation when using the Non-specific Short Range Device
(SRD) band for Telemetry, Telecommand, Alarms, Data in general
and other similar applications.
| Frequency
Band |
ERP |
Duty
Cycle |
Channel
spacing |
| E (433.050 - 434.790MHz) |
10mW |
<10% |
No spacing |
| E1 (433.050 - 434.790MHz) |
1mW |
<100% |
No spacing |
| E2
(434.040 - 434.790MHz) |
10mW |
<100% |
<25kHz |
Note: Audio and voice signals
should be avoided in the band 433.050MHz - 434.790MHzPower density
limited to -13dBm/10 kHz for wideband channels with a bandwidth
greater than 250 kHz |
|
|
Figure 5: Serial configuration of TX2I-458-5
transmitter using HyperTerminal |
| |
|
Figure 6: Maximum allowed and programmable
channels
|
| |
| Notes:
|
1.
A pause of at least 50ms must be allowed between command strings
(EEPROM programming time) SINGLE mode does not store the N value
in EEPROM. Therefore the unit is inoperative after a power down
until either another valid SINGLE command is received, or mode
is changed by a GOCHAN, SETPAR or SETSER command. SINGLE mode
is intended for frequency agile applications.
2. /SETPAR command should be issued at the end of channel programming
to put the module back into parallel frequency select mode
3. In 458MHz band, channel 12 (458.825MHz) and channel 15 (458.900MHz)
are allocated specifically for fixed alarm and radio keys/vehicle
paging applications respectively and should not be used for
general purpose applications. |
|
|
Pin description
of TX2M/RX2M with Modem mode selected
|
| The
'modem' mentioned is a 1200 baud RS232 semi-intelligent unit
(Transmit keyed when valid serial data is present, so no separate
TX control needed. Coding in the datastream also permits the
receiver to ignore noise and only output valid serial data). |
| |
|
Pin Description
- TX2M
|
|
Pin
|
Name
|
Function
|
| 1 |
0V |
Ground |
| 2 |
TXE |
Must be tied to 0V |
| 3 |
N/C |
|
| 4 |
N/C |
|
| 5 |
+4.4Vout |
DC supply. 75mA maximum drain.
Only present when TXE is low |
| 6 |
PGM |
Serial programming/configuration
input at RS232 level |
| 7 |
0V |
Ground |
| 8 |
MOD TXD (P1) |
Serial data input at RS232 level |
| 9 |
MOD N/C (P2) |
|
| 10 |
MOD TXH (P3) |
Active Low Transmit Hold for
continuous transmission (useful for test) |
| |
|
Pin Description
- RX2M
|
|
Pin
|
Name
|
Function
|
| 1 |
RSSI |
DC level between 0.5V and 2.5V.
60dB dynamic range (only valid during databursts) |
| 2 |
N/C |
|
| 3 |
N/C |
(modem tones or noise present) |
| 4 |
N/C |
(modem tones or noise present) |
| 5 |
+4.4Vout |
DC supply. 75mA max. drain.
Present if unit is powered |
| 6 |
0V |
Ground |
| 7 |
PGM |
Serial programming/configuration
input at RS232 level |
| 8 |
MOD N/C (P1) |
|
| 9 |
MOD RXD (P2) |
Modem Received Data at TTL level
(requires RS232 driver) |
| 10 |
MOD CDE (P3) |
Pull low to enable carrier detect
on modem operation (not recommended) |
|
| Condensed
specifications |
| |
| Frequency |
458.5-459.1MHz or 433-434MHz
(or any 5MHz band from 420-480MHz) |
|
Frequency
stability
|
+/- 1.5kHz |
|
Channel
spacing
|
25kHz (12.5kHz by special
order) |
|
Number
of channels
|
128 channels controlled
via RS232 interface (8 parallel selected) |
| Supply voltage |
4.5V - 16V |
| Current |
100mA nominal transmit |
| |
13mA receive |
| Operating temperature |
-10 to +60 °C
(Storage -30 to +70 °C) |
| Size |
59 x 38 x 7 mm |
| Spurious radiations |
Compliant with ETSI
EN 300 220-3 and EN 301 489-3 |
| Interface user |
10pin 0.1" pitch
molex |
|
Power
|
2pin 0.1" pitch
molex |
| RF |
3pin 0.1" pitch
molex |
| Recommended
PCB hole size |
1.2mm |
| Intended approval |
ETSI radio standard
EN 300 220-3 and EMC standard EN 301 489-3 |
| |
| Transmitter |
|
| Output power |
100mW +/- 1dB (adjustable
1 - 100mW) |
| TX on switching time |
50 ms |
| Modulation type |
FM, FSK (F1D, F3D) |
| TX modulation bandwidth |
DC - 3kHz |
| Adjacent channel TX
power |
-37dBm |
| Inputs |
analogue, data (CMOS/TTL
compatible) |
| |
|
| Receiver
|
|
| Sensitivity |
-112dBm for 1 part per
1000BER |
| |
-118dBm for 12 dB SINAD |
| image / spurious |
-70dB |
| blocking |
-85dB |
| adjacent Channel |
<-60dB (Tested per.
ETSI EN 301 489-3) |
| re-radiation |
-57dBm |
| outputs |
RSSI, carrier detect,
audio, data |
| |
|
| Power on to valid audio
(no noise mute) |
28ms |
| Power on to valid audio
(with noise mute ) |
45ms |
| Power on to stable data
out (50:50 mark / space) |
50ms (with or without
mute) |
| |
|
| Notes: |
1. The data
slicer cannot be depended upon for data waveform frequencies
below 250Hz |
| |
2. When RX is on and
a transmitter keys up, again a 50ms period is required
to stabilise data output mark/space. i.e. allow at least
50ms of preamble |
|
|
Typical current consumption
of TX2M at various RF output power level
|
|
RF power
(mW)
|
Current consumption
(mA)
|
|
100
|
90
|
|
50
|
67
|
|
25
|
54
|
|
10
|
41
|
|
5
|
35
|
|
1
|
30
|
|
| Note:
These measurements taken at 433MHz
(for 458MHz current consumption increases by about 5%) |
|
| Operating
principle of internal modem
This device is a simplex link handling
a 1200 baud asynchronous datastream (1 start, 8data, 1stop).
Buffering in the transmit end handles TX startup timing requirements,
while the presence of sync codes in the transmitted bursts
prevents the receiver from outputting garbage in the presence
of noise. No error correction or retransmission of lost packets
is supported. To operate with proper +/-12V RS232 levels an
external buffer (such as a MAX232) will be needed
Physically the modem code resides in the
PIC microcontroller which controls the radio functions. The
modem uses the internal hardware serial port of the processor.
Operation: Serial interface
Both transmit and receive modems implement
a 32 byte software FIFO. At the transmit end this is used
to allow for the TX2M transmitter start up time (about 32ms),
while on receive it buffers arriving packets to the constant
output data rate. All timing and data formatting tasks are
handled by the software. The user need not worry about keying
the transmitter before sending data: the link is entirely
transparent.
For transmission across the link data is
formatted into packets, each comprising 3 bytes of data and
a sync code. If less than 3 bytes are in the transmit end
FIFO then a packet is still sent, but idle state replaces
the unused bytes. When the transmit end FIFO is completely
emptied, then the transmitter is keyed off .
Operation: Radio interface
Raw data is not fed to the radios. A coding
operation in the transmit software, and decoding in the receiver,
isolate the AC coupled, potentially noisy baseband radio environment
from the datastream.
The radio link is fed a continuous tone
by the modem. As in biphase codes, information is coded by
varying the duration consecutive half-cycles of this tone.
In our case half cycles of 500us (a long, or L) and 250us
(a short, or S) are used.
In idle (or 'preamble') state, a sequence
of Ls is sent (resembling a 1KHz tone).
A packet comprises the Synchronising (or
address) part : LSSSSSSSSSSSSL followed by the Data part,
made up of twelve Groups (of four half cycles duration). Each
Group encodes 2 data bits, so one byte is encoded by 4 Groups.
Although there are 16 possible states for
a four half cycle group (from SSSS to LLLL), only four of
the possible states are used for valid data:
All other possible group combinations (except
LLLL) are void, and result in the entire packet being rejected
by the receiver software as a noise artifact. Idle state tone
(LLLL ....) is decoded as null data, but does not void the
packet, as a packet containing less than 3 bytes still needs
to be decoded.
The advantage of using the above coding technique:
1.Ease of decoding: Unlike biphase, where
a bit is coded as either a long half cycle or a short cycle,
here all half cycles are detected separately.
2. Inherent error detection: Although only 14 sync/address
'bits' (halfcycles) are used, the following 48 'bits' (halfcycles)
only code 24 real data bits, leading to enhanced noise/error
discrimination (the equivalent of 5 more sync bits).
3. Comparable spectral efficiency: For a maximum transmitted
baseband frequency of 2KHz, a 3 byte packet is sent in 22ms.
An equivalent biphase coded packet (comprising 19 sync + 24
data + 3 null flags) at 2kbits/sec takes 23ms
|
|
| Appendix
A |
| Transmitter
variant
RX2M is designed
to be pin and polarity compatible with existing industry standard
modules. AF and Data Output are inverted relative to original
transmitted signal.
The transmitter is available in two variants
- TX2I and TX2M
The non-inverting transmitter called TX2M
frequency modulates the carrier frequency in the normal sense
whereby higher modulating voltage increases the carrier frequency
and lower modulating voltage decreases the carrier frequency
which results in an inverted AF and Data output on the receiver.
This will be the standard module and exact plug-in replacement
for existing industry standard modules.
|
|
Figure 7: Data polarity change from
TX2M (non-inverting) to RX2M |
| |
| The inverting
transmitter called TX2I reverses the Frequency Modulating order
whereby the higher modulating voltage decreases the carrier
frequency and lower modulating voltage increases carrier frequency
which results in non-inverting AF and Data output on the receiver.
This variant can be used for applications where data inversion
will be problematic. |
|
Figure 8: Data polarity change from TX2I (inverting) to RX2M |
| |
|
| Ordering
information |
| Part
Number |
Description |
Frequency
band |
Maximum
data rate |
| TX2M-433-5 |
TX2M (non-inverting) transmitter
|
433.05MHz-434.790MHz |
5kbps |
| TX2I-433-5 |
TX2I (inverting) transmitter |
433.05MHz-434.790MHz |
5kbps |
| RX2M-433-5 |
RX2M receiver |
433.05MHz-434.790MHz |
5kbps |
| |
|
|
|
| TX2M-458-5 |
TX2M (non-inverting) transmitter |
458.525MHz-459.100MHz |
5kbps |
| TX2I-458-5 |
TX2I (inverting) transmitter |
458.525MHz-459.100MHz |
5kbps |
| RX2M-458-5 |
RX2M receiver |
458.525MHz-459.100MHz |
5kbps |
| |
|
|
|
| TX2M-458-10 |
TX2M (non-inverting) transmitter |
458.525MHz-459.100MHz |
10kbps |
| TX2I-458-10 |
TX2I (inverting) transmitter |
458.525MHz-459.100MHz |
10kbps |
| RX2M-458-10 |
RX2M receiver |
458.525MHz-459.100MHz |
10kbps |
| |
|
|
Limitation of liability
The information furnished
by Radiometrix Ltd is believed to be accurate and reliable.
Radiometrix Ltd reserves the right to make changes or improvements
in the design, specification or manufacture of its subassembly
products without notice. Radiometrix Ltd does not assume any
liability arising from the application or use of any product
or circuit described herein, nor for any infringements of
patents or other rights of third parties which may result
from the use of its products. This data sheet neither states
nor implies warranty of any kind, including fitness for any
particular application. These radio devices may be subject
to radio interference and may not function as intended if
interference is present. We do NOT recommend their use for
life critical applications.
The Intrastat commodity code for all our modules is: 8542
6000.
R&TTE Directive
After 7 April 2001 the
manufacturer can only place finished product on the market
under the provisions of the R&TTE Directive. Equipment
within the scope of the R&TTE Directive may demonstrate
compliance to the essential requirements specified in Article
3 of the Directive, as appropriate to the particular equipment.
Further details are available on The Office of Communications
(Ofcom) web site:
Licensing
policy manual
|
|
|
