There are several standards for caller id:
I'm guessing your modem does not support the BT or CCA standard but rather the Bellcore standard, that's why you can't get it to work.
- Bellcore (now Telcordia) is used in Australia, Canada, China, Hong Kong, New Zealand, Singapore and USA
- BT and CCA standards in the UK
- DTMF-based in Brazil, Belgium, Denmark, Finland, Iceland, India, Netherlands, Saudi Arabia, Sweden & Uruguay
- ETSI in Eire, France, Germany, Norway, Italy, Spain, South Africa and Turkey
- NTT standard in Japan
- "USSR ANI-hacking" in the former Soviet Union
I'm guessing your modem does not support the BT or CCA standard but rather the Bellcore standard, that's why you can't get it to work.