A user-defined telecommunication-program program communication block (TP PCB), defined by the user, that can be used to describe output message destinations other than the terminal that originated the input message. Where the keyword SAMETRM=YES is not implicitly or explicitly specified in a PSB, the destination of an alternate PCB can be either a logical terminal or an input transaction queue. See also alternate response PCB, express alternate PCB, input/output program communication block, modifiable alternate PCB.