diff --git a/src/gsm_utils.c b/src/gsm_utils.c
index 4ee137c..97497c8 100644
--- a/src/gsm_utils.c
+++ b/src/gsm_utils.c
@@ -224,7 +224,7 @@
 	if (*mhz == '\0')
 		return -EINVAL;
 
-	switch (atoi(mhz)) {
+	switch (strtol(mhz, NULL, 10)) {
 	case 450:
 		return GSM_BAND_450;
 	case 480: