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Digital Modes Interface (FT8, JS8, RTTY etc.) – Quansheng – PP5QB

Circuit proposed by Guilherme (PP5QB) to use a Quansheng HT on digital modes (FT8, JS8, RTTY, among others), connecting the radio to the computer through a USB sound card.

Interface circuit: CM108 sound card and connections to the Quansheng HT

The base is a CM108 USB sound card ("CM108 sound card", found on AliExpress). Resistors R6 and R7 (bias) must be removed from the board and, optionally, the connectors. The PTT is keyed by a BC337 transistor, which detects the transmit audio through the 1N60 diodes.