AC4490LR-200M Laird Technologies, AC4490LR-200M Datasheet - Page 64

• Manufacturer Part Number: AC4490LR-200M
• Description: TXRX 900MHZ 3.3-5.5V TTL 200MW
• Manufacturer: Laird Technologies
• Series: AeroCommr

Specifications of AC4490LR-200M

• Frequency: 902MHz ~ 928MHz
• Data Rate - Maximum: 115.2kbps
• Modulation Or Protocol: FHSS, FSK
• Applications: AMR, Fire & Security Alarms, Telemetry
• Power - Output: 5mW ~ 200mW
• Sensitivity: -110dBm
• Voltage - Supply: 3.3V, 5V
• Current - Transmitting: 68mA
• Data Interface: Connector, 2 x 10 Header
• Antenna Connector: MMCX
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Output Power: 200 mW
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Memory Size: -
• Current - Receiving: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

5 8
A P P E N D I X I I I - A P I
& C. If the repeater is set to Broadcast mode, radio A will receive a copy of each packet that it sends. If the repeater
has a specific destination address (i.e. 12 34 A2), then radio A will not receive the packet as its MAC address will not
match the specified destination address.
T I M E D I V I S I O N M U L T I P L E A C C E S S N E T W O R K
For a more intelligent network, a TDMA system can be implemented. In this system various radios transmit data to a
Shared Access Point (SAP) during an assigned time interval. The system is synchronous so that only one radio is
transmitting at a time and has full access to the SAP’s bandwidth. In a TDMA network, each radio must store its data
for the amount of time between its transmissions or bursts. A typical format for data passing through a SAP is shown
below. A frame consists of arriving bursts from remote radios and each frame is then divided into multiple time slots.
The bursts can be of varying lengths and can be longer for heavy-traffic stations. To prevent overlaps, guard intervals
can be inserted to absorb small timing errors in burst arrivals.
Example:
This type of implementation requires careful planning and should allow enough time for retries if necessary. When full
duplex is enabled, the radio which initiated the Session (SAP) will transmit during the even numbered hops and the
remote radios will transmit only during odd numbered hops.
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Shared Access Point (SAP) sends broadcast packet which includes a sync pulse
Remote radios hear the sync pulse and join the session
Radio A transmits during time interval t = 1
Radio B transmits during time interval t = 2
Radio N transmits during time interval t = N - 1
1
GB1
Radio A Data
2
GB2
TDMA Frame
1 Timeslot
Radio B Data
3
GB3
Radio C Data
4
GB4
5
6
1