Specifications

AVIDdirector-M2M™ Technical Reference Guide

2. Communicator. A Communicator is instantiated for each Radio class in the system. It performs the

interface between the M2MXML packets the calling the appropriate method for the radio to send and receive

messages. When a message is sent, the Communicator ensures the Radio has sent the message correctly or

tracks retry attempts by the Radio. Each Communicator has a queue of 25 outgoing and incoming messages. If

this queue becomes full then either the AVIDirectorApp isn't handling the messages correctly or the Radio

cannot send out the messages and a fatal Error condition is raised. This thread is monitored every 120 seconds

to allow for a long retry time for a Radio. If the Radio doesn't respond, or is hung, or the serial communication

dies, then the Communicator thread won't update the WDT and will trigger a fault condition.

3. Radio. Within the Radio, there may be threads that need to be monitored. Not all Radios require this. For

example, in the AT_Radio_Modem class, the super class for all PPP type radios (GPRS, CDMA, iDEN, XPORT

Ethernet), when the PPP link thread is alive it is monitored. When the PPP thread dies at the end of

communication, then the thread is no longer monitored and removed the list of monitored threads. Each Radio

class also monitors its own state and will raise a Fatal Error when it cannot continue correctly. For example, if

the AT_Radio_Modem class cannot establish a PPP link 5 times in a row, or the modem doesn't respond to

commands, then it wants the device to be reset.

4. IODevice. This handles all the internal I/O Devices on AVIDirector-M2M (TTL, HVC lines) and additional

I/O devices (RFID, GPS, etc.). Each I/O device is supposed to perform its operation in a minimal amount of

time, or it needs to start a thread to handle longer operations. The I/O Device drive will start to be monitored

when it starts an I/O operation and stop monitoring when the I/O operation is complete. These operations should

take less than a second, but a 60 second window is currently set to allow for longer I/O operations such as

reading an RFID tag or acquiring a GPS lock.