Selects which message(s) to retweet if the device has a GNSS compass antenna connected, and you have set a retweet IP address, and you have enabled GNSS retweet.
Talker ID on the retweeted message may be "GP" or "GN" as supplied by the antenna. For example, if GPRMC messages are enabled the message sent may be "GPRMC" or "GNRMC".