diff --git a/include/osmocom/abis/e1_input.h b/include/osmocom/abis/e1_input.h
index cf8677b..fe5d624 100644
--- a/include/osmocom/abis/e1_input.h
+++ b/include/osmocom/abis/e1_input.h
@@ -18,6 +18,7 @@
 	E1INP_SIGN_NONE,
 	E1INP_SIGN_OML,
 	E1INP_SIGN_RSL,
+	E1INP_SIGN_OSMO,	/* IPA CCM OSMO sub-type */
 };
 const char *e1inp_signtype_name(enum e1inp_sign_type tp);
 
diff --git a/src/e1_input.c b/src/e1_input.c
index e5ddaa3..0994910 100644
--- a/src/e1_input.c
+++ b/src/e1_input.c
@@ -205,6 +205,7 @@
 	[E1INP_SIGN_NONE]	= "None",
 	[E1INP_SIGN_OML]	= "OML",
 	[E1INP_SIGN_RSL]	= "RSL",
+	[E1INP_SIGN_OSMO]	= "OSMO",
 };
 const char *e1inp_signtype_name(enum e1inp_sign_type tp)
 {
diff --git a/src/input/ipaccess.c b/src/input/ipaccess.c
index b124121..8ae00d3 100644
--- a/src/input/ipaccess.c
+++ b/src/input/ipaccess.c
@@ -588,8 +588,8 @@
 
 	switch (sign_link->type) {
 	case E1INP_SIGN_OML:
-		break;
 	case E1INP_SIGN_RSL:
+	case E1INP_SIGN_OSMO:
 		break;
 	default:
 		bfd->when |= BSC_FD_WRITE; /* come back for more msg */