If the FXS ports are configured in the DIAL PLAN then they are able to provide dial tone. There is no configuration to enable or disable this.
It is possible your fax server demand is greater than the DSP resources of the ATLAS. The ATLAS 830 has 27 DSP resources. DSP resources are used to generate dial tone, generate ring back, generate digits to be propagated out of the unit, and to receive digits.
If you have an FXS module in all 8 slots, then that is 64 FXS ports. You can only get dial tone on 27 at a time. It is possible to have more than 27 calls up at once, but you can only get dial tone, ring back, etc. on 27 at a time.
There is a "Forward Disconnect" setting under the DIAL PLAN, USER TERM, in the IFCE CONFIG. This cuts the loop current for a specified period of milliseconds when the far end hangs up. Generally this should be set when connected to fax machines/servers. The default is "Disabled" but can be set to 600, 1000, or 2000 ms. Obviously the fax server would have to wait this period of time before placing an outbound call if the far end terminated the previous call.
If specific ports consistently do not get dial tone, then you should check those ports with a phone or butt set.
Hope this helps,
forward disconnect = disable. this helps no dial tone. but i have another problem. a few lines (random) could not hang up properly occasionally.
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