# RCM4000 packets over serial port

**URL:** <https://forums.digi.com/t/rcm4000-packets-over-serial-port/9384>\
**Category:** Rabbit\
**Created:** [September 21, 2009, 8:19pm UTC](https://forums.digi.com/t/rcm4000-packets-over-serial-port/9384 "2009-09-21T20:19:15Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![LeoS](https://avatars.discourse-cdn.com/v4/letter/l/b9bd4f/32.png) [@LeoS](https://forums.digi.com/u/LeoS)\
**Post date:** [September 21, 2009, 8:19pm UTC](https://forums.digi.com/t/rcm4000-packets-over-serial-port/9384/1 "2009-09-21T20:19:15Z")

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Hi,  
I have problems to comunicate packets over serial port on RCM4000. I want to implement MODBUS RTU according functions in packet.lib, but the receiving packet coming from Modbus master simulator are lost. I need some guidelines.

Thanks  
LeoS