diff --git a/main/BLE_UUID.h b/main/BLE_UUID.h
index 2828ffa..e60e383 100644
--- a/main/BLE_UUID.h
+++ b/main/BLE_UUID.h
@@ -14,6 +14,7 @@
 #define AUTO_RANGE_CHAR 0x2C15
 
 #define CHAR_PRES_FORMAT 0x2904
+#define SOURCE_GAIN_DESCR 0x2920
 
 #define PPM_UNIT_UUID 0x27C4
 #define PERCENT_UNIT_UUID 0x27AD
diff --git a/main/ble.c b/main/ble.c
index d202ea2..64bd0a4 100644
--- a/main/ble.c
+++ b/main/ble.c
@@ -56,14 +56,6 @@ static struct ble_gatt_chr_def current_measure_char_template = {
   .flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_NOTIFY,
   .min_key_size = 0,
   .val_handle = cs_handle,
-  .descriptors = (struct ble_gatt_dsc_def[]){
-    [0] = {
-      .uuid = BLE_UUID16_DECLARE(CHAR_PRES_FORMAT),
-      .att_flags = BLE_ATT_F_READ,
-      .access_cb = gatt_char_access_cs,
-    },
-    { 0 },
-  },
 };
 static struct ble_gatt_chr_def voltage_measure_char_template = {
   .uuid = BLE_UUID16_DECLARE(VOLTAGE_CHAR),
@@ -72,19 +64,44 @@ static struct ble_gatt_chr_def voltage_measure_char_template = {
   .flags = BLE_GATT_CHR_F_READ | BLE_GATT_CHR_F_NOTIFY,
   .min_key_size = 0,
   .val_handle = ev_handle,
-  .descriptors = (struct ble_gatt_dsc_def[]){
-    [0] = {
-      .uuid = BLE_UUID16_DECLARE(CHAR_PRES_FORMAT),
-      .att_flags = BLE_ATT_F_READ,
-      .access_cb = gatt_char_access_ev,
-    },
-    { 0 },
-  },
 };
 
+static struct ble_gatt_dsc_def cs_descr_template[] = {
+  [0] = {
+    .uuid = BLE_UUID16_DECLARE(CHAR_PRES_FORMAT),
+    .att_flags = BLE_ATT_F_READ,
+    .access_cb = gatt_char_access_cs,
+    .arg = NULL,
+  },
+  [1] = {
+    .uuid = BLE_UUID16_DECLARE(SOURCE_GAIN_DESCR),
+    .att_flags = BLE_ATT_F_READ,
+    .access_cb = gatt_char_access_cs,
+    .arg = NULL,
+  },
+  { 0 },
+};
 
+static struct ble_gatt_dsc_def ev_descr_template[] = {
+  [0] = {
+    .uuid = BLE_UUID16_DECLARE(CHAR_PRES_FORMAT),
+    .att_flags = BLE_ATT_F_READ,
+    .access_cb = gatt_char_access_ev,
+  },
+  [1] = {
+    .uuid = BLE_UUID16_DECLARE(SOURCE_GAIN_DESCR),
+    .att_flags = BLE_ATT_F_READ,
+    .access_cb = gatt_char_access_ev,
+  },
+  { 0 },
+};
+
+  
 static struct ble_gatt_chr_def cs_char_array[INPUTS_NUM + 1];
 static struct ble_gatt_chr_def rvs_char_array[INPUTS_NUM + 1];
+static struct ble_gatt_dsc_def cs_descr_array[INPUTS_NUM + 1][3];
+static struct ble_gatt_dsc_def rvs_descr_array[INPUTS_NUM + 1][3];
+
 
 static struct ble_gatt_svc_def gatt_svr_svcs[] = {
   [CS_SVC_ID] = {
@@ -267,16 +284,23 @@ static void generate_svc_defs(configuration* conf, measurements* meas, measureme
   
     memcpy(&cs_char_array[i], &current_measure_char_template, sizeof(current_measure_char_template));
     memcpy(&rvs_char_array[i], &voltage_measure_char_template, sizeof(voltage_measure_char_template));
-
+    
+    memcpy(&cs_descr_array[i], &cs_descr_template, sizeof(cs_descr_template));
+    memcpy(&rvs_descr_array[i], &ev_descr_template, sizeof(ev_descr_template));
+    
     uint16_t ind = i;
     
     cs_ctxt[i].handle = ind;
     cs_char_array[i].arg = &cs_ctxt[i];
     cs_char_array[i].val_handle = &cs_handle[i];
+    cs_char_array[i].descriptors = (struct ble_gatt_dsc_def*)&cs_descr_array[i];
+    cs_char_array[i].descriptors[1].arg = &cs_ctxt[i];
 
     ev_ctxt[i].handle = ind;
     rvs_char_array[i].arg = &ev_ctxt[i];
     rvs_char_array[i].val_handle = &ev_handle[i];
+    rvs_char_array[i].descriptors = (struct ble_gatt_dsc_def*)&rvs_descr_array[i];
+    rvs_char_array[i].descriptors[1].arg = &ev_ctxt[i];
   }
 
   memset(&cs_char_array[INPUTS_NUM], 0, sizeof(cs_char_array[INPUTS_NUM]));
diff --git a/main/gatt_svcs.c b/main/gatt_svcs.c
index 0f353e8..cb02de9 100644
--- a/main/gatt_svcs.c
+++ b/main/gatt_svcs.c
@@ -99,7 +99,16 @@ int gatt_char_access_cs(uint16_t conn_handle, uint16_t attr_handle, struct ble_g
       rc = os_mbuf_append(ctxt->om, &data, sizeof(data));
     break;
     case BLE_GATT_ACCESS_OP_READ_DSC:
-      rc = os_mbuf_append(ctxt->om, &current_char_pres_format, CHAR_PRESENTATION_FORMAT_SIZE);
+      ;
+      if(arg == NULL) // characteristic presentation format
+        rc = os_mbuf_append(ctxt->om, &current_char_pres_format, CHAR_PRESENTATION_FORMAT_SIZE);
+      else{
+        struct ble_context *c_ctxt = arg;
+        uint16_t handle = c_ctxt->handle;
+
+        unsigned int gain = c_ctxt->meas_ctxt->inputs[handle].gain;
+        rc = os_mbuf_append(ctxt->om, &gain, sizeof(gain));
+      }
     break;
   }
 
@@ -119,7 +128,15 @@ int gatt_char_access_ev(uint16_t conn_handle, uint16_t attr_handle, struct ble_g
       rc = os_mbuf_append(ctxt->om, &data, sizeof(data));
     break;
     case BLE_GATT_ACCESS_OP_READ_DSC:
-      rc = os_mbuf_append(ctxt->om, &raw_voltage_char_pres_format, CHAR_PRESENTATION_FORMAT_SIZE);
+      if(arg == NULL) // characteristic presentation format
+        rc = os_mbuf_append(ctxt->om, &raw_voltage_char_pres_format, CHAR_PRESENTATION_FORMAT_SIZE);
+      else{
+        struct ble_context *c_ctxt = arg;
+        uint16_t handle = c_ctxt->handle;
+
+        unsigned int gain = c_ctxt->meas_ctxt->inputs[handle].gain;
+        rc = os_mbuf_append(ctxt->om, &gain, sizeof(gain));
+      }
     break;
   }