Topic: MADI Face USB Sync

Hi,
I have a device connect to MADI Face USB:
When my device sends sync MADI signals (no data frames) I dont see that the MADI face gets into lock/sync modes. once I start sending data frames I see stable sync. when I stop sending data and keep on sending syncs only I lose the sync from the MADI Face. some details:
Frame rate = 48K
Using Coax connectors
Sync pattern is according to AES (JK)