External Machine Interface (EMI), an extension to Universal Computer Protocol (UCP) is a SMSC VAS protocol created by CMG. As one of the major SMSC vendor, EMI and SMPP are two of the widely used SMSC VAS protocol. Even after the merger of Logica and CMG, both protocols are still widely used.
One of the free library that I’ve using is from Marco Romano. It is a Perl library which can be used to generate EMI/UCP message easily. Please take a look at: