In SNA, a header, optionally followed by a response unit (RU), that indicates whether a response is positive or negative and that may contain a pacing response.; 系統(tǒng)網(wǎng)絡(luò)體系結(jié)構(gòu)(SNA)中的一種報(bào)頭，其后還可以有一個(gè)應(yīng)答單元(RU)，此報(bào)頭指明應(yīng)答 是肯定的還是否定的，而且可以包含一個(gè)調(diào)步響應(yīng)(報(bào)文)。參閱isolated pacing response, negative response, pacing response, positive response。