And the results from nRF Connect after succesfully send the command:
15:15:15,Dispositivo Conectado,verbose,Attempting to connect…
15:15:16,Dispositivo Conectado,debug,[Callback] centralManager(central, didConnect: peripheral)
15:15:16,Dispositivo Conectado,normal,Connected.
15:15:16,Dispositivo Conectado,verbose,Discovering Services…
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverServices: nil)
15:15:16,Dispositivo Conectado,normal,Discovered FEE7 y CBA20D00-224D-11E6-9FB8-0002A5D5C51B Services.
15:15:16,Dispositivo Conectado,verbose,Discovering Characteristics for FEE7…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverCharacteristics(nil, for: FEE7)
15:15:16,Dispositivo Conectado,verbose,Discovering Characteristics for CBA20D00-224D-11E6-9FB8-0002A5D5C51B…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverCharacteristics(nil, for: CBA20D00-224D-11E6-9FB8-0002A5D5C51B)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverCharacteristicsFor: FEE7, error: nil)
15:15:16,Dispositivo Conectado,verbose,Discovering Descriptors for Characteristic FEC8…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverDescriptors(for: FEC8)
15:15:16,Dispositivo Conectado,verbose,Discovering Descriptors for Characteristic FEC7…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverDescriptors(for: FEC7)
15:15:16,Dispositivo Conectado,verbose,Discovering Descriptors for Characteristic FEC9…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverDescriptors(for: FEC9)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverCharacteristicsFor: CBA20D00-224D-11E6-9FB8-0002A5D5C51B, error: nil)
15:15:16,Dispositivo Conectado,verbose,Discovering Descriptors for Characteristic CBA20003-224D-11E6-9FB8-0002A5D5C51B…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverDescriptors(for: CBA20003-224D-11E6-9FB8-0002A5D5C51B)
15:15:16,Dispositivo Conectado,verbose,Discovering Descriptors for Characteristic CBA20002-224D-11E6-9FB8-0002A5D5C51B…
15:15:16,Dispositivo Conectado,debug,peripheral.discoverDescriptors(for: CBA20002-224D-11E6-9FB8-0002A5D5C51B)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverDescriptorsFor: FEC8, error: nil)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverDescriptorsFor: FEC7, error: nil)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverDescriptorsFor: FEC9, error: nil)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverDescriptorsFor: CBA20003-224D-11E6-9FB8-0002A5D5C51B, error: nil)
15:15:16,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didDiscoverDescriptorsFor: CBA20002-224D-11E6-9FB8-0002A5D5C51B, error: nil)
15:15:16,Dispositivo Conectado,normal,Discovered Characteristics FEC8, FEC7 y FEC9 for Service FEE7.
15:15:16,Dispositivo Conectado,normal,Discovered Characteristics CBA20003-224D-11E6-9FB8-0002A5D5C51B y CBA20002-224D-11E6-9FB8-0002A5D5C51B for Service CBA20D00-224D-11E6-9FB8-0002A5D5C51B.
15:15:16,Dispositivo Conectado,normal,Discovered Client Characteristic Configuration for Characteristic FEC8
15:15:16,Dispositivo Conectado,normal,Characteristic FEC7 has no Descriptors.
15:15:16,Dispositivo Conectado,normal,Characteristic FEC9 has no Descriptors.
15:15:16,Dispositivo Conectado,normal,Discovered Client Characteristic Configuration for Characteristic CBA20003-224D-11E6-9FB8-0002A5D5C51B
15:15:16,Dispositivo Conectado,normal,Characteristic CBA20002-224D-11E6-9FB8-0002A5D5C51B has no Descriptors.
15:15:27,Dispositivo Conectado,verbose,Writing 0x57-01-00 to Characteristic CBA20002-224D-11E6-9FB8-0002A5D5C51B
15:15:27,Dispositivo Conectado,debug,peripheral.writeValue(0x57-01-00, forCharacteristic: CBA20002-224D-11E6-9FB8-0002A5D5C51B)
15:15:27,Dispositivo Conectado,application,Writing value 0x57-01-00 to Characteristic CBA20002-224D-11E6-9FB8-0002A5D5C51B
15:15:27,Dispositivo Conectado,debug,[Callback] peripheral(peripheral, didWriteValueForCharacteristic: CBA20002-224D-11E6-9FB8-0002A5D5C51B, error: nil)
15:16:06,Escáner,normal,Scanner Off.