my boss gave me a compact flash card which is IP4WW-CFVMS-C1, and ask me to test whether it is good or not.

I am not sure how to test it. First, I used a card reader, but can't read it out. I think the format is mismatched.
Then I found a SL1100 with exactly the same card, so I put it into the system, it didn't work, too.
And last, I got a inmail card PZ-VM21, put them into a SV8100, enbled 10-day temporary licence, and programmed the system as the manual says, but I just get busy tone when I dial pilot number of voicemail.

How could I know whether the flash card is working or not?

That is a 2 port Inmail for an SL1100 - When you say it didn't work on the SL1100, was it not recognized by the SL1100? Or do you just not get any voice prompts? If it wasn't recognized, the card is probably bad or software is corrupt. If you just don't hear anything when logging in, and depending on the system it came out of, it may be running an older software version - you may try doing a software upgrade to see if that helps.

As you're on Oz go to the KISS and download "In-Mail Utility Setup" and "Reliance Windows Driver". This will allow you you to restore the CF card back to factory default. If this doesn't work then it's beyond repair.

Thank you, Ken.
I just replace the good one on SL100 with the one test. When I dial voice mail pilot number just get busy tone. But the good one works well.
Does it mean the flash card is not recognized by SL1100? As the good one works, it looks like it is faulty?

Thank you, Paul. I have arrange it to get an username and password, to download the software and have a try.

Hi Paul, so for the delayed reply.
I have download the 2 software, and initialize the card. But when I dial Voice Mail pilot number, I get ring tone just as I ring an extension.
Does' it mean it is faulty?

If the license is active and the mail setup correctly then I would say so.. If you have access to another known good CF card that would prove it..