ACK Acknowledgement

AIK Application Interface Module

API Application Programming Interface

CDR Call Detail Record

ESME External Short Message Entity

MB Message Bureau

MSC Mobile Switching Centre

MS Mobile Station

NAK Negative Acknowledgement

SME Short Message Entity

SMSC Short Message Service Centre

SMPP Short Mesage Peer to Peer Protocol

VC Virtual Connection

VMA VoiceMail Alert or Message Waiting Indication

VPS Voice Processing System