I have never used them, however this table may be of some help.
I have no idea whether its up to date though - you may be better off asking the local telco. From the manual:
The following calls have II-digits values associated with them:
- Incoming ISDN PRI calls that include II-digits
- Incoming ISDN PRI Tie Trunk DCS or non-DCS calls that include II-digits
Note that, since tandeming of II-digits is only supported if the trunk facilities used
are ISDN PRI, traditional DCS does not support II-digits transport but DCS Plus
(DCS over PRI) does.
00 Identified line - no special treatment
01 Multiparty - ANI cannot be provided
02 ANI failure
06 Hotel/Motel - DN not accompanied by automatic room ID
07 Special operator handling required
20 AIOD - Listed DN of PBX sent
23 Coin or Non-Coin - line status unknown
24 800 Service
27 Coin Call
29 Prison/Inmate Service
30-32 Intercept
34 Telco Operator Handled Call
40-49 Locally determined by carrier
52 OutWATS
60 Telecommunication Relay Service (TRS) - Station Paid
61 Type 1 Cellular
62 Type 2 Cellular
63 Roaming Cellular
66 TRS - From Hotel/Motel
67 TRS - From restricted line
70 Private paystation
93 Private Virtual Network call