diff --git a/src/isdn/ph_driver.c b/src/isdn/ph_driver.c
index 53aaafe..06fb187 100644
--- a/src/isdn/ph_driver.c
+++ b/src/isdn/ph_driver.c
@@ -307,6 +307,8 @@ static void ph_socket_rx_msg(ph_socket_t *s, int channel, uint8_t prim, uint8_t
 			}
 		}
 		break;
+	case PH_PRIM_DATA_CNF:
+		break;
 	default:
 		printk(KERN_ERR "%s: Rejecting unknown message 0x%02x from PH-socket!\n", __func__, prim);
 	}