Mitel SX-200 EL Technician's Handbook page 109

Test Line Tones
Approximately ten seconds after the maintenance person enters the
test line access code on the test line set, a short ring burst, followed by
dial tone is heard, indicating that the system is waiting for the command
input. After the maintenance person enters a command sequence, the
returned tone, described in Table 18, indicates the result of the action
performed.
Table 18: Test Line Status Tones
Tone Type
Dial tone
Camp-on tone (single beep)
Reorder tone
Trunk camp-on tone (double beep)
Ringback tone (single beep or ring)
Busy Tone
Troubleshooting and Repair
Meaning
System is waiting for command input.
The attempted operation was successful
(Pass).
The attempted operation was unsuccessful
(Fail). See Note after Table 10.
Test was inconclusive.
Initial maintenance access.
Device was busy. Try again later.
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