diff --git a/src/device/isartc.c b/src/device/isartc.c
index 3ba092eb9..0128dff0a 100644
--- a/src/device/isartc.c
+++ b/src/device/isartc.c
@@ -680,11 +680,9 @@ isartc_init(const device_t *info)
 
         case ISARTC_RTC58167: /* Multitech PC-500/PC-500+ onboard RTC */
             dev->flags |= FLAG_YEARBCD;
-            //dev->base_addr   = machine_get_config_int("rtc_port");
-            dev->base_addr   = 0x2c0;
+            dev->base_addr   = machine_get_config_int("rtc_port");
             dev->base_addrsz = 8;
-            //dev->irq         = machine_get_config_int("rtc_irq");
-            dev->irq         = -1;
+            dev->irq         = machine_get_config_int("rtc_irq");
             dev->f_rd        = rtc58167_read;
             dev->f_wr        = rtc58167_write;
             dev->nvr.reset   = mm67_reset;
diff --git a/src/machine/m_xt.c b/src/machine/m_xt.c
index 5969f25c9..97e351c1b 100644
--- a/src/machine/m_xt.c
+++ b/src/machine/m_xt.c
@@ -1259,7 +1259,7 @@ static const device_config_t pc500_config[] = {
     {
         .name           = "rtc_port",
         .description    = "RTC Port Address",
-        .type           = CONFIG_HEX16,
+        .type           = CONFIG_SELECTION,
         .default_string = NULL,
         .default_int    = 0,
         .file_filter    = NULL,
@@ -1379,7 +1379,7 @@ static const device_config_t pc500plus_config[] = {
     {
         .name           = "rtc_port",
         .description    = "Onboard RTC",
-        .type           = CONFIG_HEX16,
+        .type           = CONFIG_SELECTION,
         .default_string = NULL,
         .default_int    = 0,
         .file_filter    = NULL,