The Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) offers the unique capability to collide polarized protons at high energies. One of the highlights of the polarized proton program performed at s=500GeV is that it affords the direct measurement of sea quark contribution to the proton spin via W-boson production through the measurement of the parity violating single spin asymmetry. A new trigger electronics system for forward muons, which is especially capable of W-boson detection, was developed for the PHENIX experiment. The trigger was installed as an additional electronic circuit, and it was connected in parallel with the existing cathode readout electronics of the muon tracking chamber. © 2012 Elsevier B.V. All rights reserved.