We do have the DTI Test Phone, but I've had to resort to the voice mail method. The PERRYPJ post prompted an idea. I guess it isn’t a huge convenience, but it adds a slight amount of automation, hopefully it will prompt an even better method. – something that gets you your DN faster.
From the subject phone, dial the number of the “test mailbox” you use for collecting the calling DN (this example, call 6245 for mailbox 6245).
Immediately conference in an answering machine or “device” that is capable of having this string of sounds and DTMF play (Lots of sound editors have DTMF)
Speak “Calling Number Test, Calling Number Test” then
“#79 , 816245 # 12345 # 8699272 ,,,,,,, 83”
#79 – ends message and deposits
81 – calls the logon prompt
6245# – the mailbox number plus pound
12345# - the password plus pound
8699 – goes to the last message, presumably less than the 99th
2 – starts playback
72 – plays envelope
,,,,,,, - waits during envelope
83 – disconnects
The 8699 is so you can go to the last message in case you have left previous calls that are still “new” To hear a series of messages, you’d have to log in without the answer machine
(Note that a pager that the mailbox outcalls to with the calling DN is OK, but the pager isn’t always fast enough)