# Difference between Modbus RTU and Modbus TCP?

**URL:** <https://forumautomation.com/t/difference-between-modbus-rtu-and-modbus-tcp/286>\
**Category:** Industrial Networking\
**Created:** [March 1, 2015, 7:27am UTC](https://forumautomation.com/t/difference-between-modbus-rtu-and-modbus-tcp/286 "2015-03-01T07:27:15Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![instrumen](https://forumautomation.com/letter_avatar_proxy/v4/letter/i/65b543/32.png) [@instrumen](https://forumautomation.com/u/instrumen)\
**Post date:** [March 1, 2015, 7:27am UTC](https://forumautomation.com/t/difference-between-modbus-rtu-and-modbus-tcp/286/1 "2015-03-01T07:27:16Z")

</div>

Modbus RTU is used for Serial communication ( RS-232, RS-422, RS-485). Modbus TCP is used for Ethernet Communication ( Ethernet)

---

<div class="post-metadata">

**Author:** ![scadadoctor](https://forumautomation.com/letter_avatar_proxy/v4/letter/s/ecb155/32.png) [@scadadoctor](https://forumautomation.com/u/scadadoctor)\
**Post date:** [January 20, 2016, 6:30pm UTC](https://forumautomation.com/t/difference-between-modbus-rtu-and-modbus-tcp/286/2 "2016-01-20T18:30:09Z")

</div>

Modbus serial has 2 flavors - RTU & ASCII. The main body consists of RTU address, Function code, start address, data quantity, data. The pre-emble & post-emble to the main body differs between RTU & Ascii. Modbus TCP has 2 flavors also. It is obviously on Ethernet. In more popular MBTCP version - The main body is same. The pre-emble & postemble are different. In less popular version the serial message is packed into the TCP packet envelope.