It seems that  the problem is already known and FS developers gave a workaround: https://freeswitch.org/jira/browse/FS-9765
Actually, Cisco is working incorrectly, but FreeSwitch is more flexible...

                      Thanks, __Yehavi:

‫בתאריך יום א׳, 22 בדצמ׳ 2019 ב-10:46 מאת ‪Sergey Safarov‬‏ <‪s.safarov@gmail.com‬‏>:‬
yes looks as bug, please report
https://github.com/signalwire/freeswitch/issues

https://tools.ietf.org/html/rfc6337#section-5.3

5.3. Hold and Resume of Media

[RFC3264] specifies (using non-normative language) that "hold" should be indicated in an established session by sending a new offer containing "a=sendonly" attribute for each media stream to be held. An answerer is then to respond with "a=recvonly" attribute to acknowledge that the hold request has been understood.



On Sun, Dec 22, 2019 at 11:27 AM Yehavi Bourvine <yehavi.bourvine@gmail.com> wrote:
Hi,

  Cisco sends the SDP in the ACK. The problem is that Cisco sends 'sendonly" in SDP and FS replies also with "sendonly", and there is  no apparent reason for this. This causes then a one-way audio.

            Thanks, __Yehavi:

‫בתאריך יום א׳, 22 בדצמ׳ 2019 ב-8:41 מאת ‪Sergey Safarov‬‏ <‪s.safarov@gmail.com‬‏>:‬
Think if devices send INVITE without SDP, then they must send SDP in ACK message.
Please check.

On Sun, Dec 22, 2019 at 9:02 AM Yehavi Bourvine <yehavi.bourvine@gmail.com> wrote:
Hello,
  I am connecting FS 1.8 with Cisco CUCM. A call is initiated correctly, and there is two way audio. When the Cisco phone places the call on hold, cisco sends SDP with "sendonly". Upon return from HOLD, Cisco sends INVITE without SDP  and FS replies  with SDP with "sendonly"... As a result, there is a one way audio from FS to Cisco. I can roll this problem to Cisco as it does not cancels the "sendonly" from its side, but why FS sends also "sendonly"? This probably causes Cisco to not send audio anymore.

Anyone noticed this problem and has a solution?

                     Thanks, __yehavi:
_________________________________________________________________________

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_________________________________________________________________________

The FreeSWITCH project is sponsored by SignalWire https://signalwire.com
Enhance your FreeSWITCH install with disruptive priced SMS and PSTN services.
Build your next product on our scalable cloud platform.

Join our online community to chat in real time https://signalwire.community

Professional FreeSWITCH Services
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Official FreeSWITCH Sites
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_________________________________________________________________________

The FreeSWITCH project is sponsored by SignalWire https://signalwire.com
Enhance your FreeSWITCH install with disruptive priced SMS and PSTN services.
Build your next product on our scalable cloud platform.

Join our online community to chat in real time https://signalwire.community

Professional FreeSWITCH Services
sales@freeswitch.com
https://freeswitch.com

Official FreeSWITCH Sites
https://freeswitch.com/oss
https://freeswitch.org/confluence
https://cluecon.com

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UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-users
https://freeswitch.com
_________________________________________________________________________

The FreeSWITCH project is sponsored by SignalWire https://signalwire.com
Enhance your FreeSWITCH install with disruptive priced SMS and PSTN services.
Build your next product on our scalable cloud platform.

Join our online community to chat in real time https://signalwire.community

Professional FreeSWITCH Services
sales@freeswitch.com
https://freeswitch.com

Official FreeSWITCH Sites
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https://freeswitch.org/confluence
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