initial address message (ITU-T Q723) (IAM)
The Initial Address Message (IAM) ensures that the services offered are compatible with the existing receiving devices and can be used.
The IAM message prevents, for example, a telephone from being connected to a fax machine and ensures that a user channel suitable for the service is switched.
The Initial Address Message is defined in the SS7 signaling and is part of the ISDN user part( ISUP) for connection setup. It contains information about the service, the characteristics of the user channel, ds routing and about service characteristics. The information is evaluated during the connection setup.
The Initial Address Message is described in ITU-T Recommendations Q.723, Q.762, Q.763 and Q.764.