Many computing devices configured for telecommunications (“terminals”), such as smartphones, are capable of communicating via various types of networks. For example, cellular and other portable terminals may connect with circuit-switched (CS) networks such as the Global System for Mobile Communications (GSM) or more recent packet-switched (PS) networks such as Long Term Evolution (LTE) or other Internet Protocol (IP)-based networks. Network operators often maintain legacy network devices in their networks to support older protocols or communication techniques, such as CS voice calls.