Asynchronous and/or synchronous telephony protocol systems and methods may include an asynchronous signaling node (ASN) and/or a call duration time quota from a charging onset to place and complete a call based on a first device call request as received from a first user mobile device on a packet switched network. The asynchronous systems include instructions to automatically modify the telephony address with a prefix and destination address when the first device has insufficient or independent balance or upon a network exception; route the modified call signal to the ASN; and deliver and automatically disconnect the call when the call is completed. The synchronous systems are balance-independent and include instructions to automatically set the call duration time quota upon such exception, and deliver and automatically disconnect the call from the second user telephony device when the call is completed or when the call duration time quota is exceeded.