ST60 tridata not sending data

Hi, I have an ST60 tridata instrument connected via SeaTalk to several other instruments. The speed, temp transducer is connected directly to the tridata. The tridata shows speed and temp and transmits temp via SeaTalk to the other instruments. But although it shows speed it does not send speed to the other instruments. This is preventing us from having true wind display shown. The system formerly worked properly, sending speed data and calculating true wind. It also accepts data, showing depth which comes from another instrument. Changing cabling did not help. Any ideas why this would happen?

Thanks,
Peter Malloy
S/V Neko