diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.html b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.html
index efa8e11019..a38b7e4dda 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.html
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.html
@@ -27,7 +27,10 @@
               <mat-expansion-panel-header fxLayout="row wrap">
                 <mat-panel-title>
                   <div class="title-container">
-                    {{ keyControl.get('tag').value }}{{ '-' }}{{ keyControl.get('value').value }}
+                    <span *ngIf="isMaster else tagName">
+                      {{ keyControl.get('tag').value }}{{ '-' }}{{ keyControl.get('value').value }}
+                    </span>
+                    <ng-template #tagName>{{ keyControl.get('tag').value }}</ng-template>
                   </div>
                 </mat-panel-title>
               </mat-expansion-panel-header>
@@ -73,7 +76,7 @@
                     <div class="tb-flex no-gap">
                       <mat-form-field class="tb-flex no-gap" appearance="outline" subscriptSizing="dynamic">
                         <mat-select formControlName="functionCode">
-                          <mat-option *ngFor="let code of functionCodesMap.get(keyControl.get('tag').value + keyControl.get('address').value) || defaultFunctionCodes" [value]="code">{{ ModbusFunctionCodeTranslationsMap.get(code) | translate }}</mat-option>
+                          <mat-option *ngFor="let code of functionCodesMap.get(keyControl.get('id').value) || defaultFunctionCodes" [value]="code">{{ ModbusFunctionCodeTranslationsMap.get(code) | translate }}</mat-option>
                         </mat-select>
                       </mat-form-field>
                     </div>
@@ -102,7 +105,7 @@
                       </mat-form-field>
                     </div>
                   </div>
-                  <div class="tb-form-row column-xs" fxLayoutAlign="space-between center">
+                  <div *ngIf="isMaster" class="tb-form-row column-xs" fxLayoutAlign="space-between center">
                     <div class="fixed-title-width tb-required" translate>gateway.value</div>
                     <div class="tb-flex no-gap">
                       <mat-form-field class="tb-flex no-gap" appearance="outline" subscriptSizing="dynamic">
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.ts
index 81e275b07c..ac448f703e 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-data-keys-panel/modbus-data-keys-panel.component.ts
@@ -18,7 +18,6 @@ import { Component, EventEmitter, Input, OnInit, Output } from '@angular/core';
 import { AbstractControl, FormGroup, UntypedFormArray, UntypedFormBuilder, Validators } from '@angular/forms';
 import { TbPopoverComponent } from '@shared/components/popover.component';
 import {
-  MappingKeysType,
   ModbusDataType,
   ModbusFunctionCodeTranslationsMap,
   ModbusObjectCountByDataType,
@@ -30,6 +29,7 @@ import {
 import { CommonModule } from '@angular/common';
 import { SharedModule } from '@shared/shared.module';
 import { GatewayHelpLinkPipe } from '@home/pipes/public-api';
+import { generateSecret } from '@core/utils';
 
 @Component({
   selector: 'tb-modbus-data-keys-panel',
@@ -83,11 +83,12 @@ export class ModbusDataKeysPanelComponent implements OnInit {
   addKey(): void {
     const dataKeyFormGroup = this.fb.group({
       tag: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
-      value: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
+      value: [{value: '', disabled: !this.isMaster}, [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
       type: [ModbusDataType.STRING, [Validators.required]],
       address: [0, [Validators.required]],
       objectsCount: [1, [Validators.required]],
-      functionCode: [this.getDefaultFunctionCodes()[0]]
+      functionCode: [this.getDefaultFunctionCodes()[0]],
+      id: [{value: generateSecret(5), disabled: true}],
     });
     this.observeKeyDataType(dataKeyFormGroup);
 
@@ -117,14 +118,15 @@ export class ModbusDataKeysPanelComponent implements OnInit {
         const { tag, value, type, address, objectsCount, functionCode } = keyData;
         const dataKeyFormGroup = this.fb.group({
           tag: [tag, [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
-          value: [value, [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
+          value: [{value, disabled: !this.isMaster}, [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
           type: [type, [Validators.required]],
           address: [address, [Validators.required]],
           objectsCount: [objectsCount, [Validators.required]],
           functionCode: [functionCode, []],
+          id: [{value: generateSecret(5), disabled: true}],
         });
         this.observeKeyDataType(dataKeyFormGroup);
-        this.functionCodesMap.set(tag+address, this.getFunctionCodes(type));
+        this.functionCodesMap.set(dataKeyFormGroup.get('id').value, this.getFunctionCodes(type));
 
         keysControlGroups.push(dataKeyFormGroup);
       });
@@ -138,8 +140,7 @@ export class ModbusDataKeysPanelComponent implements OnInit {
       if (!this.editableDataTypes.includes(dataType)) {
         objectsCountControl.patchValue(ModbusObjectCountByDataType[dataType]);
       }
-      const keyId = keyFormGroup.get('tag').value + keyFormGroup.get('address').value;
-      this.functionCodesMap.set(keyId, this.getFunctionCodes(dataType));
+      this.functionCodesMap.set(keyFormGroup.get('id').value, this.getFunctionCodes(dataType));
     });
   }
 
@@ -147,7 +148,7 @@ export class ModbusDataKeysPanelComponent implements OnInit {
     if (this.keysType === ModbusValueKey.ATTRIBUTES_UPDATES) {
       return this.defaultWriteFunctionCodes;
     }
-    const functionCodes = this.defaultReadFunctionCodes;
+    const functionCodes = [...this.defaultReadFunctionCodes];
     if (dataType === ModbusDataType.BITS) {
       const bitsFunctionCodes = [1, 2];
       bitsFunctionCodes.forEach(code => functionCodes.push(code));
@@ -160,6 +161,12 @@ export class ModbusDataKeysPanelComponent implements OnInit {
   }
 
   private getDefaultFunctionCodes(): number[] {
-    return this.keysType === ModbusValueKey.ATTRIBUTES_UPDATES ? this.defaultWriteFunctionCodes : this.defaultReadFunctionCodes;
+    if (this.keysType === ModbusValueKey.ATTRIBUTES_UPDATES) {
+      return this.defaultWriteFunctionCodes;
+    }
+    if (this.keysType === ModbusValueKey.RPC_REQUESTS) {
+      return [...this.defaultReadFunctionCodes, ...this.defaultWriteFunctionCodes];
+    }
+    return this.defaultReadFunctionCodes;
   }
 }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.html b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.html
index 0f30dc4314..66db8c5018 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.html
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.html
@@ -15,7 +15,8 @@
     limitations under the License.
 
 -->
-<div class="tb-form-panel no-border no-padding padding-top" [formGroup]="securityConfigFormGroup">
+<div class="tb-form-panel no-border no-padding" [formGroup]="securityConfigFormGroup">
+  <div class="tb-form-hint tb-primary-fill">{{ 'gateway.hints.path-in-os' | translate }}</div>
   <div class="tb-form-row space-between tb-flex fill-width">
     <div class="fixed-title-width" translate>gateway.client-cert-path</div>
     <div class="tb-flex no-gap">
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.ts
index 2f5786882b..bf926d3454 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-security-config/modbus-security-config.component.ts
@@ -112,7 +112,20 @@ export class ModbusSecurityConfigComponent implements ControlValueAccessor, Vali
   }
 
   writeValue(securityConfig: ModbusSecurity): void {
-    this.securityConfigFormGroup.patchValue(securityConfig, {emitEvent: false});
+    const { certfile, password, keyfile, server_hostname } = securityConfig;
+    let securityState = {
+      certfile: certfile ?? '',
+      password: password ?? '',
+      keyfile: keyfile ?? '',
+      server_hostname: server_hostname?? '',
+      reqclicert: !!securityConfig.reqclicert,
+    };
+    if (this.isMaster) {
+      securityState = { ...securityState, reqclicert: !!securityConfig.reqclicert };
+    } else {
+      securityState = { ...securityState, server_hostname: server_hostname ?? '' };
+    }
+    this.securityConfigFormGroup.reset(securityState, {emitEvent: false});
   }
 
   private observeValueChanges(): void {
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.html b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.html
index 5587cd09ee..13f31bdda5 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.html
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.html
@@ -16,6 +16,7 @@
 
 -->
 <div class="tb-form-panel no-border no-padding padding-top" [formGroup]="slaveConfigFormGroup">
+  <div class="tb-form-hint tb-primary-fill tb-flex center">{{ 'gateway.hints.modbus-server' | translate }}</div>
   <div class="tb-flex row space-between align-center no-gap fill-width">
     <div class="fixed-title-width" translate>gateway.server-slave-config</div>
     <tb-toggle-select formControlName="type" appearance="fill">
@@ -105,6 +106,15 @@
     <div class="tb-flex no-gap">
       <mat-form-field class="tb-flex no-gap" appearance="outline" subscriptSizing="dynamic">
         <input matInput type="number" min="0" name="value" formControlName="unitId" placeholder="{{ 'gateway.set' | translate }}"/>
+        <mat-icon matSuffix
+                  matTooltipPosition="above"
+                  matTooltipClass="tb-error-tooltip"
+                  [matTooltip]="('gateway.unit-id-required') | translate"
+                  *ngIf="slaveConfigFormGroup.get('unitId').hasError('required') &&
+                                           slaveConfigFormGroup.get('unitId').touched"
+                  class="tb-error">
+          warning
+        </mat-icon>
       </mat-form-field>
     </div>
   </div>
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.ts
index 4211b2b09c..27de908e11 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-config/modbus-slave-config.component.ts
@@ -23,7 +23,8 @@ import {
   UntypedFormControl,
   UntypedFormGroup,
   ValidationErrors,
-  Validator, Validators,
+  Validator,
+  Validators,
 } from '@angular/forms';
 import {
   ModbusMethodLabelsMap,
@@ -31,8 +32,11 @@ import {
   ModbusOrderType,
   ModbusProtocolLabelsMap,
   ModbusProtocolType,
+  ModbusRegisterValues,
+  ModbusSlave,
   noLeadTrailSpacesRegex,
-  PortLimits, SlaveConfig,
+  PortLimits,
+  SlaveConfig,
 } from '@home/components/widget/lib/gateway/gateway-widget.models';
 import { SharedModule } from '@shared/shared.module';
 import { CommonModule } from '@angular/common';
@@ -104,7 +108,7 @@ export class ModbusSlaveConfigComponent implements ControlValueAccessor, Validat
       port: [null, [Validators.required, Validators.min(PortLimits.MIN), Validators.max(PortLimits.MAX)]],
       serialPort: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
       method: [ModbusMethodType.SOCKET, []],
-      unitId: [null, []],
+      unitId: [null, [Validators.required]],
       baudrate: [null, []],
       deviceName: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
       deviceType: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
@@ -155,13 +159,9 @@ export class ModbusSlaveConfigComponent implements ControlValueAccessor, Validat
     };
   }
 
-  writeValue(slaveConfig: SlaveConfig): void {
-    if (slaveConfig.type === ModbusProtocolType.Serial) {
-      slaveConfig.serialPort = slaveConfig.port as string;
-      delete slaveConfig.port;
-    }
-    this.slaveConfigFormGroup.patchValue(slaveConfig, {emitEvent: false});
+  writeValue(slaveConfig: ModbusSlave): void {
     this.showSecurityControl.patchValue(!!slaveConfig.security);
+    this.updateSlaveConfig(slaveConfig);
     this.updateControlsEnabling(slaveConfig.type);
   }
 
@@ -180,4 +180,50 @@ export class ModbusSlaveConfigComponent implements ControlValueAccessor, Validat
       this.tcpUdpSpecificControlKeys.forEach(key => this.slaveConfigFormGroup.get(key)?.enable({emitEvent: false}));
     }
   };
+
+  private updateSlaveConfig(slaveConfig: ModbusSlave): void {
+    const {
+      type,
+      method,
+      unitId,
+      deviceName,
+      deviceType,
+      pollPeriod,
+      sendDataToThingsBoard,
+      byteOrder,
+      security,
+      identity,
+      values,
+      baudrate,
+      host,
+      port,
+    } = slaveConfig;
+    let slaveState: ModbusSlave = {
+      host: host ?? '',
+      type: type ?? ModbusProtocolType.TCP,
+      method: method ?? ModbusMethodType.SOCKET,
+      unitId: unitId ?? null,
+      deviceName: deviceName ?? '',
+      deviceType: deviceType ?? '',
+      pollPeriod: pollPeriod ?? null,
+      sendDataToThingsBoard: !!sendDataToThingsBoard,
+      byteOrder: byteOrder ?? ModbusOrderType.BIG,
+      security: security ?? {},
+      identity: identity ?? {
+        vendorName: '',
+        productCode: '',
+        vendorUrl: '',
+        productName: '',
+        modelName: '',
+      },
+      values: values ?? {} as ModbusRegisterValues,
+      port: port ?? null,
+    };
+    if (slaveConfig.type === ModbusProtocolType.Serial) {
+      slaveState = { ...slaveState, baudrate, serialPort: port, host: '', port: null } as ModbusSlave;
+    } else {
+      slaveState = { ...slaveState, serialPort: '', baudrate: null } as ModbusSlave;
+    }
+    this.slaveConfigFormGroup.setValue(slaveState, {emitEvent: false});
+  }
 }
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.html b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.html
index 95e7700886..3ac441447c 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.html
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.html
@@ -176,6 +176,15 @@
           <div class="tb-flex no-gap">
             <mat-form-field class="tb-flex no-gap" appearance="outline" subscriptSizing="dynamic">
               <input matInput type="number" min="0" name="value" formControlName="unitId" placeholder="{{ 'gateway.set' | translate }}"/>
+              <mat-icon matSuffix
+                        matTooltipPosition="above"
+                        matTooltipClass="tb-error-tooltip"
+                        [matTooltip]="('gateway.unit-id-required') | translate"
+                        *ngIf="slaveConfigFormGroup.get('unitId').hasError('required') &&
+                                           slaveConfigFormGroup.get('unitId').touched"
+                        class="tb-error">
+                warning
+              </mat-icon>
             </mat-form-field>
           </div>
         </div>
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.ts
index 991c71c16b..d989478e98 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/connectors-configuration/modbus/modbus-slave-dialog/modbus-slave-dialog.component.ts
@@ -125,7 +125,7 @@ export class ModbusSlaveDialogComponent extends DialogComponent<ModbusSlaveDialo
       bytesize: [null, []],
       parity: [null, []],
       strict: [false, []],
-      unitId: [null, []],
+      unitId: [null, [Validators.required]],
       deviceName: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
       deviceType: ['', [Validators.required, Validators.pattern(noLeadTrailSpacesRegex)]],
       sendDataOnlyOnChange: [false, []],
@@ -140,7 +140,7 @@ export class ModbusSlaveDialogComponent extends DialogComponent<ModbusSlaveDialo
       connectAttemptCount: [null, []],
       waitAfterFailedAttemptsMs: [null, []],
       values: [{}, []],
-      security: [],
+      security: [{}],
     });
 
     this.slaveConfigFormGroup.patchValue({
diff --git a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts
index 42a58b784e..394f6c29d0 100644
--- a/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts
+++ b/ui-ngx/src/app/modules/home/components/widget/lib/gateway/gateway-widget.models.ts
@@ -957,6 +957,7 @@ export interface ModbusSecurity {
   keyfile?: string;
   password?: string;
   server_hostname?: string;
+  reqclicert?: boolean;
 }
 
 export interface ModbusSlave {
@@ -964,6 +965,7 @@ export interface ModbusSlave {
   type: ModbusProtocolType;
   method: ModbusMethodType;
   unitId: number;
+  serialPort?: string;
   baudrate?: number;
   deviceName: string;
   deviceType: string;
diff --git a/ui-ngx/src/assets/locale/locale.constant-en_US.json b/ui-ngx/src/assets/locale/locale.constant-en_US.json
index 0475c771e6..067574b7df 100644
--- a/ui-ngx/src/assets/locale/locale.constant-en_US.json
+++ b/ui-ngx/src/assets/locale/locale.constant-en_US.json
@@ -3313,6 +3313,7 @@
         "update-config": "Add/update configuration JSON",
         "username": "Username",
         "username-required": "Username is required.",
+        "unit-id-required": "Unit ID is required.",
         "read-coils": "Read Coils",
         "read-discrete-inputs": "Read Discrete Inputs",
         "read-multiple-holding-registers": "Read Multiple Holding Register",
@@ -3322,6 +3323,7 @@
         "write-register": "Write Register",
         "write-registers": "Write Registers",
         "hints": {
+            "modbus-server": "Starting with version 3.0, Gateway can run as a Modbus slave.",
             "remote-configuration": "Enables remote configuration and management of the gateway",
             "remote-shell": "Enables remote control of the operating system with the gateway from the Remote Shell widget",
             "host": "Hostname or IP address of platform server",
@@ -3360,6 +3362,7 @@
             "grpc-max-pings-without-data": "Maximum number of keepalive ping messages that the server can send without receiving any data before it considers the connection dead.",
             "grpc-min-ping-interval-without-data": "Minimum amount of time the server should wait between sending keepalive ping messages when there is no data being sent or received.",
             "permit-without-calls": "Allow server to keep the GRPC connection alive even when there are no active RPC calls.",
+            "path-in-os": "Path in gateway os.",
             "memory": "Your data will be stored in the in-memory queue, it is a fastest but no persistence guarantee.",
             "framer-type": "Type of framer.",
             "file": "Your data will be stored in separated files and will be saved even after the gateway restart.",