# Problem on UART handshaking signals

**URL:** https://forum.sierrawireless.com/t/problem-on-uart-handshaking-signals/1411
**Category:** Open AT
**Created:** [June 19, 2007, 8:46am UTC](https://forum.sierrawireless.com/t/problem-on-uart-handshaking-signals/1411 "2007-06-19T08:46:03Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![jayemb](https://avatars.discourse-cdn.com/v4/letter/j/3e96dc/32.png) [@jayemb](https://forum.sierrawireless.com/u/jayemb)
#### Post date: [June 19, 2007, 8:46am UTC](https://forum.sierrawireless.com/t/problem-on-uart-handshaking-signals/1411/1 "2007-06-19T08:46:03Z")

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Hi all,

I am working Q24 Classics, in the UART connection, i am getting a clear response at Null Modem connection while connecting only TxD and RxD.

But in case of Hardware connection, while utilising all the 9 pins, i am not getting reponse from handshaking signals.  
Especially when DTR, RTS is asserted to 0, we are not getting 0 logic level at the DSR and CTS pins.  
Instead of that when i send my data, i receiving the data at RxD, CTS and DSR pins.  
Because of these problem’s, i am not receiving any response for AT commands.

Also i am sure that the RS232 miscellaneous connections are good, i suspect on the H/W or S/W settings with wireless CPU and OpenAT.

Kindly help me