The IP Office IP500V2 Combination Card ATM (700504556) combines multiple station and trunk ports with voice over IP resources in a single cost-effective card. This item can only be used on IP500v2 chassis. Enhancements for IP500 Combination Card V2: Impedance matching to trunk characteristics, improved echo reduction, and reduction of occasional noise It Provides combination of 6 x Digital (DS) ext ports, 2 x analogue ext ports, 4 x analogue trunk ports Maximum of 2 Combination cards, installed in any slot are supported on IP500v2. Compatible only with IP500 V2 control unit running IPO 8.1 Feature Pack 1 (8.1.63) or higher Digital station (DS) ports compatible with Avaya 1400, 2400, 5400, 6400, and 9500 series digital telephones