RS232C TTL to RS485 Conversion

[astrouk1 0]

Hi All,

 

I have an LG LVC-M513HP camera module that has connections: Ground, TxD & RxD (for RS232C TTL Level). My DVR has a standard RS485 connection for PTZ control. The connection is only required to control the zoom on the camera. Does anyone have any idea on the best way to convert this signal?

 

I have seen TTL-RS232 and RS232-RS485 adaptors, would both of these together solve the problem?

 

Any assistance much appreciated.

 

Astrouk1.

[dynaco 0]

It looks like you have not had response by a knowledgeable regular so I will give you my best guess.

 

RS-232 and TTL are two very different animals. The voltage levels on TTL are typically 0 to +5V while on RS-232C they are typically -12V to +12V. Based on what you said the connections indicated, I tried to find a manual to find out what the voltage levels really were but could only find a spec sheet that clearly indicated as, you said, "Camera Control: RS232C(TTL Level)" which does leave one a little confused.

 

That being said, TTL is not generally used between devices. In addition, the TTL is enclosed in parentheses and you indicate the connections are labeled Ground, TxD & RxD. All of these facts would strongly suggest to me that it is RS-232 and as result you would only need a RS-232 to RS-485 converter.

 

I would however want more than a guess by a stranger if I was hooking it up. I would look closely at the manual again and see if there is anything more definitive or a reference to what the actual voltage levels are. If the manual is not more specific, I might even contact LG support directly and ask they mean exactly by "RS232C(TTL Level)".

 

Perhaps now a more knowledgeable person will step in and elaborate further. Good luck