The hang-up disposition refers to how a call ended.

Send_bye - This message shows our system ended the call
Recv_bye - This indicates that we received a call ended notification.
Recv_cancel - This message shows that the recipient canceled the call.
send_cancel - This message shows that our system aborted the call

This is a general status on the call showing the following:

Successful - The call made successfully and the recipient picked up
Failed - The call was not made successfully due to an system issue
Unanswered- The call was made successfully, but the recipient did not pick up

These are reports that accompany a hang up disposition, they offer more insight on the call. 

THE_NORMAL_UNSPECIFIED:  This cause is used to report a normal event only when no other cause in the normal class applies.
NETOWRK_OUT_OF_ORDER: This cause indicates that the network connectivity to the telco is not functioning correctly and that the condition is likely to last a relatively long period of time e.g. immediately re-attempting the call is not likely to be successful.
NORMAL_CLEARING: This means that the call ended as expected and it was a normal call ending
ORIGINATOR_CANCEL: This means that the source of the call disconnected the call.
NO_ANSWER:  This means that there was no response to the call made
USER_BUSY: This cause is used to indicate that the called party is unable to accept another call because the user busy condition has been encountered/engaged on another call.
NO_USER_RESPONSE: This cause is used when a called party does not respond to a call establishment message with either an alerting or connect indication within the prescribed period of time allocated.
SUBSCRIBER_ABSENT: This cause us used to report when the called party's network provider is unable to establish a signal with the end party.
SERVICE_UNAVAILABLE: This cause is used to report a service not available.
USER_NOT_REGISTERED: This means you tried to originate a call to a SIP user who forgot to register/hasn't registered.
UNALLOCATED_NUMBER: This cause indicates that the called party cannot be reached because, although the called party number is in a valid format, it is not currently allocated (assigned).
DESTINATION_OUT_OF_ORDER: This cause indicates that the destination indicated by the user cannot be reached because the interface to the destination is not functioning correctly. The term "not functioning correctly" indicates that a signal message was unable to be delivered to the remote party; e.g. a physical layer or data link layer failure at the remote party, or user equipment off-line.

REJECTED - CALLER_FILTERED_OUT: Experienced when the whitelist option is activated. Where numbers in the whitelist are the only one allowed to call a number.

NORMAL_TEMPORARY_FAILURE: Received after retries were made to reach the telecom service provider

RECOVERY_ON_TIMER_EXPIRE: Experienced after the maximum number of concurrent calls provided to our provider by the telecom was reached.

INCOMPATIBLE_DESTINATION error received by the provider's server when unable to process the request.

Reach out to support@mteja.io with any questions you may have regarding caller hang up dispositions.