Optional additional package for all communication systems of type ES 5xx up, ES 54x, ES 6xx, ES 7xx [each from system firmware 1.7] and ES PURE-IP! Scope of services: enables the activation of 6 additional voice boxes that can be freely assigned via call distribution. Including Voice To Mail function for sending the recorded messages as a wav file to a desired destination address. System expansion up to 12 (ES 542) / 18 (ES 546 and 548) / 24 (ES PURE-IP) / 30 (ES 6xx) / 60 (ES 73x) / 120 (ES 77x) voiceboxes possible!