An interface device (100) for interfacing between a network device (170-240) and a software-defined networking (SDN) controller (150), the interface device (100) comprising: a first interface (140) for connecting the interface device (100) to the SDN controller (150); a second interface (160) for connecting the interface device (100) to the network device (170-240); a vendor and technology specific layer module (110), which is operative to transmit control and message data to, and to receive control and message data from, the network device (170-240) in a native control and message data protocol of the network device; a device abstraction layer module (120), which is operative to generate a device abstraction model (400) representing capabilities of the network device (170-240); and a protocol mapping layer module (130), which is operative to map control and message data used by the network device (170-240) onto the device abstraction model (400), such that messages issued by the SDN controller (150) in its native message format can be transmitted to the network device in a native message format of the network device (170-240), and messages issued by the network device (170-240) in its native message format can be transmitted to the SDN controller (150) in the native message format of the SDN controller (150).

A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.

A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.

A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.

A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.

A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.

A sender telephone receives a text message to send to a receiver telephone. The sender telephone determines the transmission delay time by sending a predetermined message to receiver telephone, based on the time it receives an address complete message and a release message. The sender telephone determines a constant value that is greater than the transmission delay time and in response to the determining the constant value, ringing the receiver telephone to transmit the received inputted text message. A receiver telephone receives a predetermined message from a caller telephone to determine a transmission delay time, based on the time it receives the address complete message and a release message. The receiver telephone determines a constant value that is greater than the transmission delay time. The receiver telephone receives incoming rings from the caller telephone and converts the received rings into a text message to be displayed.