XT09-PKI-EA Digi International/Maxstream, XT09-PKI-EA Datasheet - Page 49

no-image

XT09-PKI-EA

Manufacturer Part Number
XT09-PKI-EA
Description
MODEM RF 900MHZ 1W ETHER W/ACC
Manufacturer
Digi International/Maxstream
Series
XTend™r
Datasheet

Specifications of XT09-PKI-EA

Function
Transceiver, Modem
Modulation Or Protocol
FHSS, FSK
Frequency
900MHz
Interface
RJ-45 Ethernet
Sensitivity
-110dBm
Data Rate - Maximum
10 kbps
Voltage - Supply
7 V ~ 28 V
Package / Case
Module
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Features
-
Power - Output
-
Applications
-
9XTend‐PKG‐E™ Ethernet RF Modem – Product Manual v2.x4x [2007.01.04]
5.2.3. Repeater Mode
Theory of Operation
Attributes:
Constraints:
Suggestions:
Required Parameter Values (TX modem): MD = 5 or 6, MY = unique value (can be accom-
plished by issuing the AM (Auto-set MY) and WR (Write) commands to all modems in the network)
Related Commands: Networking (MD, DT, MY, AM), Serial Interfacing (RN, PK, RO, RB)
Recommended Use: Use in networks where intermediary modems are needed to relay data to
modems beyond the transmission range of the base modem.
OEMs and integrators can extend the effective range and reliability of their data radio system by
forwarding traffic through one or more repeaters. Instead of using routing tables and path discov-
ery to establish dynamic paths through a network, the repeater system uses a sophisticated algo-
rithm to propagate each RF packet through the entire network.
The network supports RF packets up to 2048 bytes (when the RF data rate is set at 9600 bps (BR
= 0)). The repeater network can operate using broadcast or addressed communications for multi-
drop networks and works well in many systems with no special configuration.
When in Repeater Mode, the network repeats each message among all available modems exactly
one time. This mechanism eliminates the need for configuring specific routes.
Figure 5‐06. Repeater Network Topology
© 2007 MaxStream, Inc., Confidential & Proprietary ‐ All Rights Reserved 
Low power consumption
Minimized interference
Each RF packet is tagged with a unique Packet ID (PID).
Each repeater will repeat a packet only once (tracked by the PID).
Increased latency and decreased throughput
(Latency and throughput is determined by number of hops, not by number of
repeaters. Multiple repeaters within range of source node count as one hop.)
All RF packets propagate to every modem in the network (filtering rules apply).
Packet destination addresses (DT) determine which packets are sent out serial
port and/or retransmitted.
Broadcast communications - each packet comes out every node exactly once.
Addressed communications - all modems see every packet. Only the modem
with a matching address will forward it to the DO buffer (UART IN).
Requires that each modem have a unique MY (Source Address) parameter.
System must introduce just one packet at a time to the network for transmission
(Maximum number of bytes is determined by the PK parameter).
Each hop (H) decreases network throughput by a factor of 1/(H+1). Additional
repeaters add network redundancy without decreasing throughput.
Insert a variable delay before repeating packets to avoid collisions
(based on RSSI).
Buffer any incoming serial data and delay response packet transmissions until
previous packet has cleared out of network.
For best results, use the RO and RB commands to ensure that the RF packets
align with the underlying protocol packets as the network can only accept one RF
packet at a time.
     49

Related parts for XT09-PKI-EA