When a PSTN call is put on hold by a Lync client (this may happen explicitly by clicking the appropriate button or implicitly by placing a second call for consultation or answering a call waiting) the PSTN gateway may play Music on Hold (MOH) to the participant on the PSTN side. This is not a mandatory requirement for qualification but customers typically expect that behaviour.
The OfficeMaster Gate products from Ferrari electronic AG support that by default. The gateways include a built-in music which was especially designed and licensed for that purpose. Administrators can disable it or replace it by an individual MOH file. The size of this file is only limited by available mass storage space – the small 4BRI box and the PCIe gateway board in the Survivable Branch Appliance (SBA) both use a 4GB memory card for operating system and data. Typical available space is 1-2GB which could be used for a MOH file. The 1U gateways with 4 or 8 PRI use conventional hard disks so there is even more space available.
MOH files must be in raw G.711 a-law format with 8000 samples/second. Existing audio files can easily be converted using tools like Audacity or Goldwave. Target format must be uncompressed, 8000 samples, RAW (without header) with PCM a-law codec. The resulting file can then be imported through the OfficeMaster Gate configuration tool: