4700 Duke Drive, Suite 200
Ultra-Long-Range, General Purpose
900MHz Radio Telemetry Module
12 April-2011
Revision 1.1
Cincinnati Technologies
4700 Duke Dr. Suite 200
Mason, OH 45040
4700 Duke Drive, Suite 200
900 MHz Radio Telemetry Module Description
This document describes the features and architecture for a general purpose 900 MHz
telemetry transceiver module with exceptionally long range and reliable communications.
Architecture
Radio Standard and IC Selection
The module is designed around the Atmel AT86RF212 802.15.4 transceiver IC. The
802.15.4 radio standard is an especially good choice as it provides for operation un der the
FCC CFR 15.247 spread spectrum rules, at significantly higher transmit power levels than
would otherwise be allowed. The engineers at Cincinnati Technologies have engaged in the
development of spread spectrum radio products and technologies for two decades,
beginning with the design and manufacture of the first spread spectrum residenti al cordless
telephone in 1992.
Transmit Power Level
For small, low duty cycle battery-powered applications transmitters oper ating at 50-100
milliwatts have been found to work well. It is high enough to achieve excellent range and
coverage but low enough in DC power consumption to work well with AA cells.
Data Rate and Receiver Sensitivity
The AT86RF212 transmitted data rate is software selectable from 20 kbits/second to 1000
kbits/second. Higher data rates will yield longer battery life due to shorter transmitter on
times. Lower data rates yield better receiver sensitivity and longer range. This tradeoff is
easily optimized for each application.
Integrated Diversity Antennas
The benefits gained by use of two antennas are twofold. First, in environments rich in RF
reflections, a phenomenon known as multi-path fading will frequently reduce the received
signal level. A second antenna with different radiation characteristics will have different
fades.
The second benefit is based on the fact that antennas do not perform equally in all directions.
By using two antennas with pattern nulls in different directions the module can choose to
operate with the antenna with the lowest path loss to the far end.
4700 Duke Drive, Suite 200
Frequency Agility
Incorporation of automatic ability to change operating frequency helps the radio pair avoid
disruption due to on-channel interference. FCC rules mandate that products must tolerate
occasional interference. One of the best strategies for doing so is avoidance.
Radio Control
It is desirable that integration of this module into various products be as simple as possible.
This is achieved by use of the microcontroller to manage many basic radio and network
functions.
Interface
Pin # Pin Type Description
1 GND P Ground
2 VCC P Power supply
3 SLEEP I Sleep mode input
4 SCK I SPI clock
5 SDI DI SPI data input
6 SDO DO SPI data output
7 CS I SPI chip select
8 TX DO UART Tx
9 RX DI UART Rx
10 RESET I Reset
11 INT O Interrupt request output
12 GPIO I/O May be used for standalone
applications
Electrical Specifications
Transmit Current 200mA max
Receive Current 15 mA max
Sleep Current 5 uA max
Radiated Transmit Power 22.97 dBm EIRP typical
Radiated Receive Sensitivity 50 dBuV/m typical at 40 kbits/second
4700 Duke Drive, Suite 200
FCC STATEMENT:
1. This device complies with part 15 of the FCC Rules. Operation is subject to the following
two conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received, including interference that may c aus e
undesired operation.
2. Changes or modifications not expressly approved by the party responsible for compliance
could void the user's authority to operate the equipment.
NOTE: This equipment has been tested and found to comply with the limits for a Class B
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide
reasonable protecti on against harmful int erference in a residential installation. This
equipment generates, uses and can radiate radio frequency energy and, if not installed and
used in accordance with the instructions, may cause harmful interference to radio
communications. However, there is no guarantee that interference will not occur in a
particular installation. If this equipment does cause harmful interference to radio or television
reception, which can be determined by turning the equipment off and on, the user is
encouraged to try to correct the interference by one or m ore of the following measures:
-- Reorient or relocate the receiving antenna.
-- Increase the separation between the equipment and receiver.
-- Connect the equipment into an outlet on a circuit different from that to which the receiver is
connected.
-- Consult the dealer or an experienced radio/TV technician for help.
FCC Radiation Exposure Statement
The modular can be installed or integrated in mobile or fix devices only. This modular cannot
be installed in any portable device, for example, USB dongle like transmitters is forbidden.
This modular complies with FCC RF radiation exposure limits set forth for an uncontrolled
environment. This transmitter must not be co-located or operating in conjunction with any
other antenna or transmitter. This modular must be installed and operated with a minimum
distance of 20 cm between the radiator and user body.
If the FCC identification number is not visible when the module is installed inside another
device, then the outside of the device into which the module is installed must also display a
label referring to the enclosed module. This exterior label can use wording suc h as the
following: “Contains Transmitter Module FCC ID: DI2CTLM901
when the module is installed inside another device, the user manual of this device must
contain below warning statements;
1. This device complies with Part 15 of the FCC Rules. Operation is subject to the following
two conditions:
4700 Duke Drive, Suite 200
(1) This device may not cause harmful interference.
(2) This device must accept any interference received, including interfere nce that may cause
undesired operation.
2. Changes or modifications not expressly approved by the party responsible for compliance
could void the user's authority to operate the equipment.
The devices must be installed and used in strict accordance with the manufacturer's
instructions as described in the user documentation that comes with the product.
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