diff --git a/src/rsl.c b/src/rsl.c
index 62cd562..6ba1375 100644
--- a/src/rsl.c
+++ b/src/rsl.c
@@ -124,7 +124,7 @@
 		subch &= 0x01;
 		break;
 	case RSL_CHAN_SDCCH4_ACCH:
-		subch &= 0x07;
+		subch &= 0x03;
 		break;
 	case RSL_CHAN_SDCCH8_ACCH:
 		subch &= 0x07;