On Hold with ATA device

We are using an old phone system phones that are really meant for pots lines. The problem that we are having is that when we press hold on the phone hold music doesn’t play. I assume this is because the ATA is no signaling the PBX that the call is on hold. I have researched this a bit and I don’t seem to find anything other than using a MOH server with in the ATA device. We are using the Linksys RTP300 any help or suggestions would be greatful!

It is unlikely that the hold button on the phone will signal the PBX to place the call on hold. What type of phones are these?

The ATA does not know you are on hold either. The way to place a call on hold with an ATA is to send a hookflash. Local hold on the phones merely keeps the line active and mutes the audio.