More lines-more power. Turn your Edge E series phone into a high performance attendant console with the Poly Edge EM expansion module. Each expansion module serves up three pages of 22 dedicated key appearances-66 contacts/speed dials total, right at your fingertips. Add up to two Poly Edge EM expansion modules to a Poly Edge E500/E550 phone. Add one Poly Edge EM expansion module to a Poly Edge E400/E450 phone.