Caller ID will have problems, fact. D* will send out a thousand techs to fix something that cant be fixed. It is a feature that should not be live as its so buggy becuase of 911/fcc regulations. In my area Embarq CID works 50% of the time and Verizon about 25% of the time.
Nutshell, If its not working right, it wont. There have been tech bulletins about it for years but CSR's still for some stupid reason give callers hope.
What happens is, the modem is so sensitive that if it was in the middle of a call and you had to call 911 (or anything for that matter), it would give you a dial tone before you could get it to your ear. Embarq's DSL frequencies interfere with that restriction essentially permanently turning your modem off.