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.

An online concierge system for establishing a communication session between devices using a light signal. A first client device captures video data depicting a light emitter of another client device. The first client device detects a light signal transmitted by the light emitter in the video data. The first client device extracts a handshake identifier from the light signal by decoding the light signal. A machine learning model may be used to translate the light signal into a numerical or an alphanumerical identifier. The first client device established a communication session with the other client device by transmitting a request to establish the communication session via an online concierge system. The request contains the extracted handshake identifier.

An online concierge system for establishing a communication session between devices using a light signal. A first client device captures video data depicting a light emitter of another client device. The first client device detects a light signal transmitted by the light emitter in the video data. The first client device extracts a handshake identifier from the light signal by decoding the light signal. A machine learning model may be used to translate the light signal into a numerical or an alphanumerical identifier. The first client device established a communication session with the other client device by transmitting a request to establish the communication session via an online concierge system. The request contains the extracted handshake identifier.