The invention relates to a novel red emitting material of 2Si5\u2014a\u2212bAlaN8\u2212a\u22124bOa+4b having an average particle size distribution d50 of >6 \u03bcm, with 0. The inventive method is suitable particularly for establishing a connection for call image transmission between SIP supporting telephones and non-SIP supporting telephones. The membrane can have a varied width across its length so that its ends have different widths.