# Serial Miniature Bluetooth Receive Problem

**URL:** <https://community.sparkfun.com/t/serial-miniature-bluetooth-receive-problem/1130>\
**Category:** Wireless & IoT\
**Created:** [November 30, 2005, 12:34am UTC](https://community.sparkfun.com/t/serial-miniature-bluetooth-receive-problem/1130 "2005-11-30T00:34:02Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![sumguy16](https://avatars.discourse-cdn.com/v4/letter/s/3e96dc/32.png) [@sumguy16](https://community.sparkfun.com/u/sumguy16)\
**Post date:** [November 30, 2005, 12:34am UTC](https://community.sparkfun.com/t/serial-miniature-bluetooth-receive-problem/1130/1 "2005-11-30T00:34:02Z")

</div>

I have been working with the Serial Miniature Bluetooth for awhile now and have been able to transmit from the BlueTooth Remote to the PC at every possible baud rate. I have been trying for about the past week to transmit from the PC to the remote device. I have hooked up an o-scope and I get a constant level of 5V+ on the Tx Pin, is this normal? I cannot get anything to come out of the Tx pin other than logic level high. I may have tried to transmit on the Tx pin before at 5Vdc, would this damage the remote module?

Thanks,

Adam

---

<div class="post-metadata">

**Author:** ![sparky](https://yyz1.discourse-cdn.com/sparkfun/user_avatar/community.sparkfun.com/sparky/32/6021_2.png) [@sparky](https://community.sparkfun.com/u/sparky)\
**Post date:** [December 11, 2005, 9:13pm UTC](https://community.sparkfun.com/t/serial-miniature-bluetooth-receive-problem/1130/2 "2005-12-11T21:13:43Z")

</div>

Hi,

The BlueSMiRF is 5V tolerant so that should not have been a problem. I don’t think you could have done damage by hooking TX to TX. We fully test all units before we ship. We can certainly test the unit for you.

Email spark @ [sparkfun.com](http://sparkfun.com)

-Nathan

---

<div class="post-metadata">

**Author:** ![Paul](https://avatars.discourse-cdn.com/v4/letter/p/bbe5ce/32.png) [@Paul](https://community.sparkfun.com/u/Paul)\
**Post date:** [March 5, 2006, 1:27pm UTC](https://community.sparkfun.com/t/serial-miniature-bluetooth-receive-problem/1130/3 "2006-03-05T13:27:57Z")

</div>

> sumguy16:  
> I have been working with the Serial Miniature Bluetooth for awhile now and have been able to transmit from the BlueTooth Remote to the PC at every possible baud rate. I have been trying for about the past week to transmit from the PC to the remote device. I have hooked up an o-scope and I get a constant level of 5V+ on the Tx Pin, is this normal? I cannot get anything to come out of the Tx pin other than logic level high. I may have tried to transmit on the Tx pin before at 5Vdc, would this damage the remote module?
> 
> Thanks,
> 
> Adam

Hi, I think that is because you are not converting the TTL output of BlueSMiRF to RS232 level required to transmit data to a computer.

Paul