开云体育

Hi Neil,

We are using Yaesu FT-7900 radios for Packet Communication within our local ARES/RACES group and those radios are a good choice for that purpose.

As others have already mentioned, do use the 6-Pin data connector at the back of the radio. The one pitfall that exists with the 6-pin mini-DIN connector is that it offers two audio output signals (pins 4 and 5). Audio output on the data connector depends on the Menu Setting #26 (PKT.SPD = Packet Speed) which depending on your radio interface cable needs to be set to 1200 (receiver audio on pin 5) or 9600 (discriminator audio on pin 4).

Important: the Packet Speed setting controls the audio output for the data port. It is irrelevant what the actual data rate is that you are using. However high-speed data (9600 baud packet, VARA-FM wide) generally requires bypassing deemphasis and therefore the need to use pin 4. For 1200 baud packet or VARA-FM narrow either audio pin will work.
Again (since this is a common mistake), the menu setting controls the audio output on the data connector and needs to match the way your cable is wired. The radio does not care about the baud rate of your signal.

You may also want to set menu #25 (PKT.MIC = Packet Microphone) to disable the microphone for a radio dedicated to packet use.

You do need to use a proper hardware PTT signal. This can be a GPIO pin from the Raspberry Pi but see the DIrewolf User's Guide? for a number of other ways to produce a good PTT signal. There are DRA models (from Masters Communications) that have mini-DIN6 connectors which means you only need a straight-through cable to connect the radio to any computer with USB port. The DRA uses a GPIO pin on the audio interface to produce PTT for the radio,
This makes the Direwolf configuration easy as well (just "PTT CM108" will do in that case).

73,
Thomas
KK6FPP