I’ve recently deployed an Audiocodes Mediant 1000 (AC M1K) gateway integrated with Microsoft Lync 2013, and encountered an interesting obstacle.
On the telephony side, the AC M1K was configured to use ISDN PRI T1 (23 bearer channels, and 1 data channel) using the NI2 protocol. On the IP side, the AC M1K was configured to integrate to Lync 2013 via SIP protocol, TCP transport, using port 5068. Basic inbound and outbound calls were working as expected, but when placing a PSTN call on hold (from the Lync side), the held person was experiencing a “beep” hold-tone every 5 seconds.
At first, “Music on Hold” (MOH) in the Lync client policy was configured as “False”. Upon switching this to “True”, the held PSTN caller heard “default” Lync MOH. However, the desired experience for on hold callers was silence.
While tracing the Lync to PSTN call on hold via “ACSyslog”, as soon as the call was placed on hold I could see the AC M1K triggering the following event:
“PlayTone - Called Tone=HELD_TONE Direction=PLAY_TONE_2_TEL”.
This seemed to indicate that the tone was coming from the AC M1K. To configure the gateway to play silence when a Lync user places a PSTN call on hold, I had to upload a modified tone template file to the AC M1K that changed the “hold tone” to “silence”. This “Call Progress Tone” file was built by and obtained directly from AudioCodes Support, and isn’t available on their public website.
Once uploaded, the unit had to be restarted, and after that PSTN calls placed on hold by a Lync client no longer experienced the “beep” hold-tone every 5 seconds – they just maintain silence for the duration of the hold, as desired.
Contact Enabling Technologies for assistance with this or any of your Lync, Skype for Business, and/or Audiocodes configuration and troubleshooting needs! Info@enablingtechcorp.com