Hi I observe what you just described quite often. You are likely to have listened the JA call through DPLUS linking. If the JA station was not routing to your repeater directly, your One-Touch did not work because your repeater/gateway did not have his(her) originating gateway information.
Gateway routing (e.g., UR=/JA1YJXA) should have worked. But if (s)he did not announce the repeater callsign, then... no way. Regards, 73, -- JI1BQW - Kay Ishikawa
