I'll take the first part. You are transmitting in C4FM (very similar to P25, but not the same protocol or vocoding or data rate), a 4-level direct frequency shift keying transmitting data at 1.2 kbps. It occupies a 6.25 kHz channelspace and is very similar to (but still different) NXDN. It's FDMA, so it is FM, but nothing you can hear without a compatible decoder.When using d star are you still transmitting in FM and AM modes? Second question with a standard dongle or other types of dongles (not a d star dongle) can you receive and transmit d star.
Please read the answer closely however since the term "receive/transmit" may not be exactly what you're thinking when you picture it. The phrase "connect to the international D-Star gateway network" is probably the key to this answer. You don't directly use a radio with a dongle, but you talk through a D-Star Gateway's radio over the internet from your computer to actually transmit over the air. This gateway may be local so you can talk to folks nearby, but it also can be thousands of miles away.What is it?
When a DV Dongle is connected to a PC or Mac and used with DVTool software, an amateur radio operator can connect to the international D-Star gateway network and receive/transmit just like a D-Star radio user.