The PSKR modes use binary convolution to generate two bits per varicode bit at the same symbol rate. These modes us Rate R=1/2, Constraint length K=7 with diagonal interleavers, variable in size to keep the timing between redundant information constant.
The number of interleavers for each baud rate is 40, 80 and 160 for PSK125R, PSK250R and PSK500R respectively. PSKR modes use the MFSK varicode which provides a small increase in average speed of about 13%.
The PSK63FEC (also PSK63F in short) is identical to the PSKR modes but for the absence of an interleaver.
Mode Speed WPM Duty Cycle Bandwidth ITU Designator
PSK125R 125 baud 110 wpm ~ 80% 250 Hz 250HG1B
PSK250R 250 baud 220 wpm ~ 80% 500 Hz 500HG1B
PSK500R 500 baud 440 wpm ~ 80% 1000 Hz 1000HG1B