Chapter 2. Getting Started the BHT and System Mode
PING Echo Request Send Timing (SEND TYPE)
Two types of echo request send timings are available: TYPE 1 and TYPE 2.
■TYPE 1
After sending an echo request, PING will wait for the period specified by INTERVAL and then send an echo request again. For TYPE 1, the relationship between the INTERVAL and TIMEOUT should be "INTERVAL ≥ TIMEOUT."
Sends an echo request
Receives an echo reply 
Timeout period
Interval
Sends an echo request
■TYPE 2
After sending an echo request, PING will wait for an echo reply to be received or for timeout to occur. After that, PING will wait for the period specified by INTERVAL and then send an echo request again. For TYPE 2, no relationship between the INTERVAL and TIMEOUT is required.
If PING receives an echo reply:
Sends an echo request
Receives an echo reply
Interval
Sends an echo request
If timeout occurs:
Sends an echo request
Timeout period
Timeout occurs
Interval
Sends an echo request
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