The Richtlinie Notrufverbindungen (TR Notruf) of the Bundesnetzagentur requires to send address information within call signaling of an emergency call. This requirement is for OpenScape 4000 subscribers, DSS1 and SIP trunks in Germany.

The address information is added to the LIN table entries. Call Processing reads the address information in case of an emergency call, packs it into an ISDN User Info Element and sends it in the ISDN SETUP message to the Central Office. Trunks to a Central office which do not support TR Notruf are marked with a Class of trunk parameter (NOEA) and address information is not sent. The latter functionality is needed in multinational OpenScape 4000 deployments.

Normal treatment is given to User Info elements received from the Central Office, e.g the element is passed on to devices and/or applications.