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CL2510
RF Transceiver
THEORY OF
OPERATION
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The CL2510 utilizes a Server-Client configuration to synchronize the frequency hopping of all devices in the
network. The Server transmits a brief beacon immediately after hopping to a new frequency. This beacon
contains information about the network and the hopping pattern. Client radios will synchronize to this beacon
to ensure they are on the same frequency at the same time as the Server. The Client Link LED will light when
the Client is synchronized to the Server.
Each network should consist of only one Server and there should never be two Servers on the same RF
Channel and System ID in the same coverage area. Collocated Servers are permitted, provided the Servers
are on different RF Channels. Additional Servers in the same coverage area will degrade the performance for
all radios. Interference will increase a maximum of 2.3% for each Server added when hopping over 43 hops
and a maximum of 1.2% when hopping over 79 hops. Degradation may be transparent to the end user
depending on the number of retries/attempts and the data rate.
mODES OF OPERATION
The CL2510 has two primary modes of operation:
Transparent Mode
Command Mode
Transmit mode is used to transmit serial data across the RF and Command Mode is used to reconfigure
the CL2510.
TRANSmIT mODE
All packets sent over the RF are either Broadcast or Addressed (Unicast) packets.
BROADCAST PACKETS
A Broadcast Packet is one that can be received by all eligible receivers on the network. To increase the
reliability of the delivery of Broadcast packets, the transmitting radio will transmit the message the number
of times specified by the Broadcast Attempts. Broadcast Attempts are necessary because Broadcast packets
are not acknowledged by the receiving radio. Therefore, the transmitting radio has no method for guaranteeing
receipt of the message. The default Broadcast Attempts is 3 and more or less may be necessary in different
applications. Increasing Broadcast Attempts will increase the reliability of data at the cost of the overall
throughput potential of the link. The receiving radio will not forward duplicate Broadcast packets on to the
OEM host.
ADDRESSED PACKETS
An Addressed Packet is one that is only sent to a specific transceiver based upon the MAC address of the
destination. Addressed packets are acknowledged by the receiving radio, so additional Transmit Retries will
only be used if necessary. The transmitting radio will retry sending an Addressed Packet until all of the
Transmit Retries have been used or until it receives a successful acknowledgement from the receiving radio.
COmmAND mODE
Command Mode is used to configure the transceiver. To enter Command Mode on the CL2510 the OEM host
must send the AT Enter Command string "AT+++". Once in Command Mode, all data received by the radio
over the serial interface is interpreted as command data. Data received over the RF interface will be stored in
the TX buffer until Command Mode is exited.
When using the Laird Technologies Configuration Utility, the OEM doesn't need to worry about entering and
exiting Command Mode, as the software will do that automatically. These details on Command Mode are pro-
vided for OEMs manually configuring the radio.
* Design Tip: Entering Command Mode.
A properly formed Enter AT Command string must be issued when the RX Serial buffer on the radio is empty.
If data is either pre-pended or added to the AT string, the radio will not properly identify it as the AT Enter
Command Mode command and will not enter Command Mode. It is suggested that the OEM host wait a
sufficient period of time between the last data packet and the AT Enter Command Mode. This time varies
depending on the amount of data being sent and the number of retries/attempts configured. Waiting at
least 250ms should be sufficient for most applications.
Laird Technologies
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