This object is included as a variable-binding in RSSI or Ec/Io threshold notifications to identify which specific radio service (for example 1xRTT, EV-DO, or GSM) triggered the alert. An admin reading a signal-quality trap needs this field to know which underlying radio technology the accompanying RSSI or Ec/Io reading actually came from, since a device may support multiple services simultaneously. For example, if a c3gRssiOnsetNotif trap arrives with this object set to the EV-DO service, the admin knows the weak-signal reading applies specifically to the EV-DO radio, not the 1xRTT one.