# \[SOLVED\] Read 3 bytes from Serial Port

**URL:** <https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800>\
**Category:** Bindings\
**Created:** [February 26, 2019, 12:00am UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800 "2019-02-26T00:00:13Z")\
**Posts on this page:** 14\
**Page:** 1

<div class="post-metadata">

**Author:** ![Fridolin22](https://community.openhab.org/user_avatar/community.openhab.org/fridolin22/32/33974_2.png) [@Fridolin22](https://community.openhab.org/u/Fridolin22)\
**Post date:** [February 26, 2019, 12:00am UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/1 "2019-02-26T00:00:13Z")

</div>

I need to read from serial port 3 bytes and process them afterwards. It’s for a light switch with up to 6 buttons.

Format is as following:  
first byte:  
 - current status  
 - button pressed/released  
second byte:  
number of wall switch  
third byte:  
00 - no button pressed  
01-06 - number of button which is pressed

Testdata read with minicom from serial port RS232:

```auto
ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 00 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 bb 02 08 ff 02 08 ff 03 00 ff 04 00 bb 02 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 bb 02 04 ff 04 00 ff 05 00 ff 06 00 bb 02 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 0c ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 0c ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 0c ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 0c ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 0c ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 bb 02 04 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 bb 02 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 09 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00 ff 06 00 ff 1f 00 ff 20 08 ff 01 00 ff 02 08 ff 03 00 ff 04 00 ff 05 00

```

How can I read 3 bytes and give them some logic? I also want the function “long pressed” to dim the light. I’m completely new to this and don’t know where to start.

Thanks for any help or hints!

---

<div class="post-metadata">

**Author:** ![rlkoshak](https://community.openhab.org/user_avatar/community.openhab.org/rlkoshak/32/75251_2.png) [@rlkoshak](https://community.openhab.org/u/rlkoshak)\
**Post date:** [February 26, 2019, 3:36pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/2 "2019-02-26T15:36:04Z")

</div>

You would use the Serial binding. I think you will need to use both the REGEX and Base64.

> **[Serial - Bindings](https://v2.openhab.org/addons/bindings/serial1/)**
>
> The Serial binding allows openHAB to communicate over serial ports attached to the openHAB server.

The REGEX will need to match the three bytes you want.

---

<div class="post-metadata">

**Author:** ![Fridolin22](https://community.openhab.org/user_avatar/community.openhab.org/fridolin22/32/33974_2.png) [@Fridolin22](https://community.openhab.org/u/Fridolin22)\
**Post date:** [February 26, 2019, 5:13pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/3 "2019-02-26T17:13:06Z")

</div>

Thanks for answering. I already played around with this binding but without success. I just don’t see the hex values to be able to do the REGEX.

If i use this items file (without BASE64):

```csv
String serialsT1 "Key1 [%s]" { serial="/dev/ttyAMA0@9600"}

```

This is the result:

```auto
18:02:31.438 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ������� to ������
18:02:32.069 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ������ to �� ����
18:02:32.584 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from �� ���� to ���� �
18:02:33.207 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ���� � to ������
18:02:33.836 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ������ to � �����
18:02:34.457 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from � ����� to ��� ���
18:02:35.075 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ��� ��� to ����� �
18:02:35.701 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ����� � to ������
18:02:36.224 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from ������ to � ����
18:02:36.870 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from � ���� to ���� ��

```

If I use this items definition (with BASE64):

```csv
String serialsT1 "Key1 [%s]" { serial="/dev/ttyAMA0@9600,BASE64"}

```

This is the result:

```auto
18:05:59.410 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG to 77+9AQDvv70CAO+/vQMA77+9BADvv70FAO+/vQYA
18:06:00.038 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AQDvv70CAO+/vQMA77+9BADvv70FAO+/vQYA to 77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA
18:06:00.762 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA to 77+9BQDvv70GAO+/vR8A77+9IAfvv70BAO+/vQIA77+9AwA=
18:06:03.259 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BQDvv70GAO+/vR8A77+9IAfvv70BAO+/vQIA77+9AwA= to 77+9BADvv70FAO+/vQYA77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA77+9BQDvv70GAO+/vR8A77+9IAbvv70BAO+/vQIA77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG77+9AQDvv70CAO+/vQMA
18:06:03.882 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BADvv70FAO+/vQYA77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA77+9BQDvv70GAO+/vR8A77+9IAbvv70BAO+/vQIA77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG77+9AQDvv70CAO+/vQMA to 77+9BADvv70FAO+/vQYA77+9HwDvv70gBu+/vQEA
18:06:04.714 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BADvv70FAO+/vQYA77+9HwDvv70gBu+/vQEA to 77+9AgDvv70DAO+/vQQA77+9BQDvv70GAO+/vR8A77+9IAbvv70BAA==
18:06:05.233 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AgDvv70DAO+/vQQA77+9BQDvv70GAO+/vR8A77+9IAbvv70BAA== to 77+9AgDvv70DAO+/vQQA77+9BQDvv70GAA==
18:06:05.958 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AgDvv70DAO+/vQQA77+9BQDvv70GAA== to 77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA77+9BQA=
18:06:06.491 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA77+9BQA= to 77+9BgDvv70fAO+/vSAG77+9AQDvv70CAA==
18:06:07.113 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BgDvv70fAO+/vSAG77+9AQDvv70CAA== to 77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG
18:06:07.731 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG to 77+9AQDvv70CAO+/vQMA77+9BADvv70FAO+/vQYA
18:06:08.354 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AQDvv70CAO+/vQMA77+9BADvv70FAO+/vQYA to 77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA
18:06:08.987 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9HwDvv70gBu+/vQEA77+9AgDvv70DAO+/vQQA to 77+9BQDvv70GAO+/vR8A77+9IAbvv70BAO+/vQIA
18:06:09.610 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BQDvv70GAO+/vR8A77+9IAbvv70BAO+/vQIA to 77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG

```

What I’m doing wrong so I don’t get the 3 byte HEX values which I could then pass via REGEX to an item and use in rules to update values?

Thanks for any comments!

---

<div class="post-metadata">

**Author:** ![rlkoshak](https://community.openhab.org/user_avatar/community.openhab.org/rlkoshak/32/75251_2.png) [@rlkoshak](https://community.openhab.org/u/rlkoshak)\
**Post date:** [February 26, 2019, 5:16pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/4 "2019-02-26T17:16:51Z")

</div>

Probably the easiest thing will be to just set a String Item to the full message (Base64) and use String manipulation inside a Rule to extract the values you need.

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [February 26, 2019, 5:51pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/5 "2019-02-26T17:51:41Z")

</div>

I think if you look at `serialsT1.state.toString` it will look more like the bytes you expect.

---

<div class="post-metadata">

**Author:** ![Fridolin22](https://community.openhab.org/user_avatar/community.openhab.org/fridolin22/32/33974_2.png) [@Fridolin22](https://community.openhab.org/u/Fridolin22)\
**Post date:** [February 26, 2019, 9:32pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/6 "2019-02-26T21:32:15Z")

</div>

Thanks for the inputs.

Tried now with rule and BASE64 but still no correct data. I’m frustrated…

My current items file:

```csv
String serialsT1 "Key1 [%s]" { serial="/dev/ttyAMA0@9600,BASE64"}

```

My current rule:

```php
import javax.xml.bind.DatatypeConverter

rule "check values"
when
    Item serialsT1 changed 
then
    logInfo("rule check values", "serial value: "+DatatypeConverter::parseBase64Binary(serialsT1.state.toString()))
end

```

Log entries:

```auto
22:30:36.743 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BQDvv70GAO+/vR8A77+9IAfvv70BAe+/vQIA77+9AwA= to 77+9BADvv70FAO+/vQYA77+9HwDvv70gBg==
22:30:36.756 [INFO] [rthome.model.script.rule check values] - serial value: [B@c70c91
22:30:37.375 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BADvv70FAO+/vQYA77+9HwDvv70gBg== to 77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA
22:30:37.390 [INFO] [rthome.model.script.rule check values] - serial value: [B@1ef0856
22:30:38.009 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA to 77+9HwDvv70gBu+/vQEB77+9AgDvv70DAO+/vQQA
22:30:38.016 [INFO] [rthome.model.script.rule check values] - serial value: [B@1b5511a
22:30:38.633 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9HwDvv70gBu+/vQEB77+9AgDvv70DAO+/vQQA to 77+9BQDvv70GAO+/vR8A77+9IAbvv70BAe+/vQIA
22:30:38.651 [INFO] [rthome.model.script.rule check values] - serial value: [B@1b00477
22:30:39.251 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BQDvv70GAO+/vR8A77+9IAbvv70BAe+/vQIA to 77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG
22:30:39.268 [INFO] [rthome.model.script.rule check values] - serial value: [B@1efb1c4
22:30:39.865 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AwDvv70EAO+/vQUA77+9BgDvv70fAO+/vSAG to 77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA
22:30:39.871 [INFO] [rthome.model.script.rule check values] - serial value: [B@15338da
22:30:40.385 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA to 77+9HwDvv70gBu+/vQEB77+9AgDvv70DAA==
22:30:40.396 [INFO] [rthome.model.script.rule check values] - serial value: [B@11ccf35
22:30:41.010 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9HwDvv70gBu+/vQEB77+9AgDvv70DAA== to 77+9BADvv70FAO+/vQYA77+9HwDvv70gBu+/vQEB
22:30:41.032 [INFO] [rthome.model.script.rule check values] - serial value: [B@180c522

```

As long as I can’t read the data correctly REGEX can’t be used.

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [February 26, 2019, 9:50pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/7 "2019-02-26T21:50:53Z")

</div>

> [@rossko57](#):
>
> I think if you look at `serialsT1.state.toString` it will look more like the bytes you expect.

At least let us see what you are feeding this DatatypeConverter

---

<div class="post-metadata">

**Author:** ![Fridolin22](https://community.openhab.org/user_avatar/community.openhab.org/fridolin22/32/33974_2.png) [@Fridolin22](https://community.openhab.org/u/Fridolin22)\
**Post date:** [February 26, 2019, 9:59pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/8 "2019-02-26T21:59:21Z")

</div>

Added a line in rules to show value of _serialsT1.state.toString_:

enabled also DEBUG mode on serial binding, but didn’t gave any valueable data.. 😥

```php
import javax.xml.bind.DatatypeConverter

rule "check values"
when
    Item serialsT1 changed 
then
    logInfo("plain value", "serial plain value:"+serialsT1.state.toString)
    logInfo("rule check values", "serial value: "+DatatypeConverter::parseBase64Binary(serialsT1.state.toString()))
end

```

```auto
22:56:21.635 [DEBUG] [.binding.serial.internal.SerialDevice] - Received message '���� �����' on serial port /dev/ttyAMA0
22:56:21.660 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BgDvv70fAO+/vSAG77+9AQHvv70CAO+/vQMA77+9BAA= to 77+9BQDvv70GAO+/vR8A77+9IAfvv70BAe+/vQIA77+9AwDvv70EAO+/vQUA
22:56:21.730 [INFO] [se.smarthome.model.script.plain value] - serial plain value:77+9BQDvv70GAO+/vR8A77+9IAfvv70BAe+/vQIA77+9AwDvv70EAO+/vQUA
22:56:21.742 [INFO] [rthome.model.script.rule check values] - serial value: [B@1ea91a1
22:56:22.776 [DEBUG] [.binding.serial.internal.SerialDevice] - Received message '��� �������� ' on serial port /dev/ttyAMA0
22:56:22.807 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BQDvv70GAO+/vR8A77+9IAfvv70BAe+/vQIA77+9AwDvv70EAO+/vQUA to 77+9BgDvv70fAO+/vSAG77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA77+9HwDvv70gBg==
22:56:22.831 [INFO] [se.smarthome.model.script.plain value] - serial plain value:77+9BgDvv70fAO+/vSAG77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA77+9HwDvv70gBg==
22:56:22.847 [INFO] [rthome.model.script.rule check values] - serial value: [B@a083e9
22:56:23.608 [DEBUG] [.binding.serial.internal.SerialDevice] - Received message '�������� ' on serial port /dev/ttyAMA0
22:56:23.645 [INFO] [smarthome.event.ItemStateChangedEvent] - serialsT1 changed from 77+9BgDvv70fAO+/vSAG77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA77+9HwDvv70gBg== to 77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA77+9HwDvv70gBg==
22:56:23.656 [INFO] [se.smarthome.model.script.plain value] - serial plain value:77+9AQHvv70CAO+/vQMA77+9BADvv70FAO+/vQYA77+9HwDvv70gBg==
22:56:23.675 [INFO] [rthome.model.script.rule check values] - serial value: [B@1fb1adb

```

---

<div class="post-metadata">

**Author:** ![rlkoshak](https://community.openhab.org/user_avatar/community.openhab.org/rlkoshak/32/75251_2.png) [@rlkoshak](https://community.openhab.org/u/rlkoshak)\
**Post date:** [February 26, 2019, 10:10pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/9 "2019-02-26T22:10:41Z")

</div>

The values you are getting from the binding are Base64. When you decode the Base64 you end up back to raw bytes.

To use the REGEX you need to do so on the Base64 encoded value.

Otherwise you need to do binary manipulation with is not easy to do in Rules DSL.

You will not be able to look for “ff 05 00”.

You will have to do a little looking to see how Base64 encoding works so you can figure out which Base64 characters represent the hex values.

Or you will have to figure out how to manage and work with pure binary data. Look at how to do this in Java as there is no native support in Xtend for this. But the Java classes are available in Xtend so what ever examples you find in Java will apply to Rules.

---

<div class="post-metadata">

**Author:** ![pboos](https://community.openhab.org/user_avatar/community.openhab.org/pboos/32/71874_2.png) [@pboos](https://community.openhab.org/u/pboos)\
**Post date:** [February 27, 2019, 7:33am UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/10 "2019-02-27T07:33:28Z")

</div>

Writing for @Fridolin22 (working on this together with him).

We got it to work to print the serial value. It seems kind of okay, but is different from what we actually should get. We get lines like:

```
EF BF BD 01 00 
EF BF BD 02 00 

```

So somehow it seems like we get EF BF BD instead of FF. But the question is why? If we check the serial directly (with minicom) then we get FF 01 00 correctly. So it has to happen somewhere on the way.  
Could it be that the conversion from byte to String in the SerialBinding is causing the problem? Would there be any way around that?

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [February 27, 2019, 11:43am UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/11 "2019-02-27T11:43:23Z")

</div>

EF BF BD is the UTF-8 “replacement” character, shows up as � in the log strings.  
Somewhere you’ve got UTF-8 encoding, probably by a default setting. Think you have to get into EXTRA\_JAVA\_OPTS to change this. Or if you’re scripting, who cares so long as its consistent?

---

<div class="post-metadata">

**Author:** ![Fridolin22](https://community.openhab.org/user_avatar/community.openhab.org/fridolin22/32/33974_2.png) [@Fridolin22](https://community.openhab.org/u/Fridolin22)\
**Post date:** [February 27, 2019, 12:57pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/12 "2019-02-27T12:57:14Z")

</div>

Thanks for the answer. Any suggestion what would be the correct charset?

---

<div class="post-metadata">

**Author:** ![rossko57](https://community.openhab.org/user_avatar/community.openhab.org/rossko57/32/70263_2.png) [@rossko57](https://community.openhab.org/u/rossko57)\
**Post date:** [February 27, 2019, 1:11pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/13 "2019-02-27T13:11:13Z")

</div>

> [@Fridolin22](#):
>
> Any suggestion what would be the correct charset?

No idea. What is “correct”?  
This might help

> [@Strange problem with serial binding](https://community.openhab.org/t/strange-problem-with-serial-binding/43230/2):
>
> I think I already found the cause of this. The probem seams to be that Openhab binding constructs a string from the bytes to pass this to the rules and it does that with the default charset: sb.append(new String(readBuffer, 0, bytes)); My guess is that the default charset is UTF-8, so i changed this to ISO-8859-1: sb.append(new String(readBuffer, 0, bytes, Charset.forName(“ISO-8859-1”))); And now it seams to work perfectly! The question is if this should be the default charset or if this sho…

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<div class="post-metadata">

**Author:** ![Fridolin22](https://community.openhab.org/user_avatar/community.openhab.org/fridolin22/32/33974_2.png) [@Fridolin22](https://community.openhab.org/u/Fridolin22)\
**Post date:** [February 27, 2019, 10:01pm UTC](https://community.openhab.org/t/solved-read-3-bytes-from-serial-port/68800/14 "2019-02-27T22:01:10Z")

</div>

Thanks all for the help/hints.

Finally we where able to solve it as following:

- System is still running with Locale UTF-8. No need to change it nor to change any EXTRA\_JAVA\_OPTS definitions. Just add “CHARSET(ISO-8859-1)” to items definition.

items file:

```csv
String serialsT1 "key1 [%s]" { serial="/dev/ttyAMA0@9600,CHARSET(ISO-8859-1),BASE64" }

```

rules file:

```php
import javax.xml.bind.DatatypeConverter

rule "check values"
when
    Item serialsT1 changed 
then
    val char[] hexArray = "0123456789ABCDEF".toCharArray()

    val byte[] bytes = DatatypeConverter::parseBase64Binary(serialsT1.state.toString())

    val char[] hexChars = newCharArrayOfSize(bytes.length() * 2)
    for ( var j = 0; j < bytes.length(); j++ ) {
        var int v = bytes.get(j).bitwiseAnd(0xFF)
        hexChars.set(j * 2, hexArray.get(v >>> 4))
        hexChars.set(j * 2 + 1, hexArray.get(v.bitwiseAnd(0x0F)))
    }
    val outString = new String(hexChars)
    logInfo("rule check values", "serial value: " + outString)

    for (String command : outString.split("(?=FF)|(?=BB)")) {
        logInfo("rule check values", "command: " + command)
    }
end

```