This variable indicates what type of code is being sent across
the DS3 interface by the device. Setting this variable causes
the interface to begin sending the code requested.
The values mean:
ds3SendNoCode
sending looped or normal data
ds3SendLineCode
sending a request for a line loopback
ds3SendPayloadCode
sending a request for a payload loopback
(i.e., all DS1s in a DS3 frame)
ds3SendResetCode
sending a loopback deactivation request
ds3SendTestPattern
sending a test pattern.