noun
signalling protocol
Technical term in computing and telecommunications for the set of rules governing signal exchange between devices.
この通信システムでは、信号手順に従ってデータが送受信される。
In this communication system, data is sent and received according to the signalling protocol.
プロトコル is a broader term for any protocol, while 信号手順 specifically refers to the signalling aspect, often at a lower level.
Compound of 信号 (signal) and 手順 (procedure, steps).