cnReach N500 User Guide
Technical Reference
phn-4673_002v000 (March 2018)
3-3
Data may be transferred in either direction. Data transfer speeds can be manipulated using the Max
Payload Bytes and Dynamic Payload settings. Refer to the
configuration information.
PMP Protocol Characteristics
•
Any number of slaves or end points may attach to the master.
•
The Master doesn’t keep track of which slaves are present – any slave may attempt to communicate with
master.
•
The Master transmits data downstream in broadcast mode.
•
The Master repeats each transmitted packet a configured number of times.
•
Slaves or End Points respond with a request for attention if they have data to transmit.
•
Master responds to an attention request with an attention grant, but data from master is still broadcast to
all.
•
If slave fails to get master’s attention due to a collision, it employs a random back-off algorithm to decide
when to request attention again.
•
Once a slave has the master’s attention, it may transmit data in response to each master packet; other
slaves must not transmit.
•
Master acknowledges receipt of slave transmission, along with continued broadcast data.
•
Slave relinquishes master attention when done transmitting data, or after a configured limit.
•
Master may revoke its attention from a slave if a configured number of consecutive receive errors occur, or
if the slave does not relinquish attention after a configured limit.
•
While a slave has the master’s attention, the master acknowledges the slave’s transmitted packets. If the
slave fails to receive an “acknowledge” after a configured number of transmissions, it drops the packet and
begins transmitting the next packet.
Additional Characteristics in PMP Ethernet Mode
•
The Master and slave use the destination MAC address in a packet to distinguish Ethernet broadcast packets
from Ethernet addressed packets.
•
Slave determines which MAC addresses are currently behind it, up to a limit.
•
Any slave may acknowledge a packet addressed to one of its known MAC addresses; master stops
repeating the packet when it receives the acknowledgement.
•
If no slave has master attention, an acknowledging slave transmits the acknowledge packet without
requesting master attention.
•
If one slave has master attention, other slaves may not acknowledge.
Transmit Power and RSSI
Transmit Power is set in milli-Watts. The range will vary depending on the radio band and region code.
The recommendation is to not set the power level below 100mW.
mW can be converted to dBm using this
Summary of Contents for cnReach N500
Page 1: ...User Guide cnReach N500 System Release 01 30 900 MHz 700 MHz 450 MHz 220 MHz ...
Page 17: ...Chapter 1 Product Description cnReach N500 Radio Module ...
Page 70: ...cnReach N500 User Guide System Configuration phn 4673_003v000 November 2018 2 38 ...
Page 77: ...cnReach N500 User Guide System Configuration phn 4673_003v000 November 2018 2 45 ...
Page 82: ...cnReach N500 User Guide System Configuration phn 4673_003v000 November 2018 2 50 ...
Page 117: ...cnReach N500 User Guide Technical Reference phn 4673_002v000 March 2018 3 5 ...
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