The SPA 112 can be used to connect to a SIP voice system. This would be provided by your Internet Telephone Service Provider (ITSP).
The device is an analog telephone adapter, that allows your analog phone to make and receive call through the ITSP.
Answering the call is handled by picking up the handset. The SPA doesn't really answer the call.
If you are talking about the call going to voicemail, the number of rings to forward to another line or to voicemail is usually handled by the provider, usually in the configuration panels they provide for your account.
There is a feature that lets you forward the call from the phone if there is no answer. Dial *92, then the number to forward to. (this doesn't sound like your question tho.
Cfwd No Ans Act Code
Forwards no-answer calls to the extension specified after the activation code.
The default is *92.
Here's the info page for the ATA
http://www.cisco.com/en/US/products/ps11977/index.html
The data sheet link is at the bottom, which has all the features, capablilities, etc.
The administration guide has more information, and is located here:
http://www.cisco.com/en/US/docs/voice_ip_comm/csbpvga/ata/administration/guide/ATA_AG_v3_NC-WEB.pdf
Let me know if you have any more questions.
Dan
