as referenced in sparkfun “RF Link 4800bps Receiver - 315MHz” Receiver Datasheet?
-thanks
I work in the field and have never heard of HCS modulation. Either it’s something odd or it was an error in the poor translation to English.
Maybe HCS is related to Holtek - who makes the very popular 4 or 8 bit encoder/decoder chips.
Further investigation shows that HCS is a registered trademark of Microchip. It’s a Hopping Code encoding / decoding method used in KEELOQ Remote Keyless Entry; the primary purpose of the 315 and 433 Mhz allocation. It supports 4 different keypresses. Don’t know if it’s a 00-11 or 0000-1111 on the TX side yet and whether it’s serial OOK, stepped ASK levels, or PWM. I’ll continue to look into it when my 315MHX TX and RX modules arrive from Sparkfun as I was already planning to experiment with fixed period / variable pulse width modulation to increase the data rate via duty cycle modulation. Now maybe I’ll try stepped amplitude with a programmable attenuator on the TX module output and try reading ASK levels on the RX modules linear output pin 3. More info is in Microchip app note AN824