This answer mentions a "basic ICAP address". What is a basic ICAP address and what are its benefits and disadvantages over "regular" ICAP addresses?
A basic ICAP address basicly is a regular ICAP address. It's the most simple type of ICAP available consisting only of the account identifyer
XE and the 31 bytes composed from the raw hex ethereum address.
The direct ICAP address has an IBAN-compatible account identifyer
XE, a checksum like
73 and the rest of the address is composed of the last 30 bytes of the hex ethereum key. This only works if the first byte of the ethereum key is zero as per specification.
I guess the more interesting question would be, what are indirect ICAP addresses? ;-)