You can use Not Ready reason codes without Web Client. Web Client gives you the additional ability to see those codes on your Real Time displays. With just SCCS, you can run reports on the Not Ready codes, but cannot view them realtime.
You'll need to first set it up in the PBX. First, make sure you have feature package 155 (ACNT).
Then, make sure you have an ADS block configured in LD 23. Then, on the ACD queue that the phones are programmed in, answer Yes to NRAC. The agent phones need to have an ACNT key.
In Symposium, configure your Not Ready codes in the Activity Codes section -- that gives them a name for your reports.