Some satellites also support RTTY and SSTV in this mode. This mode is unique in that it can be done with a simple HF rig. JD - This mode stands for J Digital and requires a 2 meter FM transmitter and a 70 cm receiver and supports packet.
Some satellites have dual modes that operate simultaneously.
For example, some can operate in mode BS which means that it can do both mode B and mode S simultaneously. This is useful to detect when the satellite has crossed the horizon and is in range for operation. It can also be used to determine doppler shifts. It accepts a range of frequencies on the input and retransmits the entire range on the output. All offsets within that range are preserved.