This read-write enumeration, applying to P-SDLC and S-SDLC protocols only, enables or disables the group poll feature, which when enabled polls multiple secondary stations at once using the address set in ifwanGroupAddress. An administrator enables this to reduce polling overhead on a multidrop SDLC line by addressing several secondaries simultaneously rather than one at a time. For example, enabling group poll on a line with many secondary terminals would speed up the overall polling cycle compared to polling each station individually.