atcomsystems.ca/forum Forums Other TDM Phone Systems Sprint - Tadiran Telephones & Systems SIP Terminal Grandstream HT-502 problem on IPXoffice

Hi,
I just hookup my Grandstream HT502 to my Tadiran IPXOffice.
This ATA box works fine between my other ATA Box(SPA2100). But when I call from HT-502 to any Tadiran phone (such as; T207M), I cannot hear anything but T207M hear my voice.
So my Grandstream works between ATA to ATA, but it's kind of oneway between ATA to T207M.
Do I need to change the default setting on HT502?
Please and appreciated for you help

regards.
Dendiko