TTL to RS-422
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Posts: 46,084
Hi everyone!
I am working on a science fair project that involves rf
communication. I got my hands on two really nice radio modems from
electrowave however the only problem is that they are in RS-422
protocall where as the stamp is TTL. I purchased some ic's that I
think will do the conversion. The part #is DS75176BN and the data
sheet is at http://www.national.com/ds/DS/DS75176B.pdf . However I
cannot figure out what connections I need to make to/from this
converter. Im not familiar with the RE, RO, DE, DI, ect.
abbriviations that are on the data sheet, so I'm not sure what goes
to the stamp and what goes to the modem. Can anyone please help
me?? Thanks
Jason Schuler
I am working on a science fair project that involves rf
communication. I got my hands on two really nice radio modems from
electrowave however the only problem is that they are in RS-422
protocall where as the stamp is TTL. I purchased some ic's that I
think will do the conversion. The part #is DS75176BN and the data
sheet is at http://www.national.com/ds/DS/DS75176B.pdf . However I
cannot figure out what connections I need to make to/from this
converter. Im not familiar with the RE, RO, DE, DI, ect.
abbriviations that are on the data sheet, so I'm not sure what goes
to the stamp and what goes to the modem. Can anyone please help
me?? Thanks
Jason Schuler
Comments
Have a look at http://www.hw.cz/english/docs/rs485/rs485.html and
http://www.maxim-ic.com/appnotes.cfm/appnote_number/723.
RS-422 uses twisted pair, so two wires will go out to the bus.
/RE is the receive enable. RO is the output to the Stamp, DI is the
input from the Stamp's output. DE is the transmit enable. DO and /DO are
the bus outputs. With 422, one side transmits and the other receives, so
you'd only use half of this hooked up to the Stamp (input or output). DE
has to be low while receiving. For short runs you probably don't need a
termination resistor.
Does that help?
Al Williams
AWC
* Floating point math for the Stamp, PIC, SX, or any microcontroller
http://www.al-williams.com/awce/pak1.htm
>
Original Message
> From: jasonsch312 <schuler_jason@h...>
> [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=aEb3IHgSZ2YFwQZ6SOe6cenia45Lci4B6_YLy-x97A6MVtlZn84psmZqUDRQXZ0BGpzyLZfWOq-FvbtoOxq7HcZjdA]schuler_jason@h...[/url
> Sent: Friday, January 03, 2003 10:43 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] TTL to RS-422
>
>
> Hi everyone!
>
> I am working on a science fair project that involves rf
> communication. I got my hands on two really nice radio modems from
> electrowave however the only problem is that they are in RS-422
> protocall where as the stamp is TTL. I purchased some ic's that I
> think will do the conversion. The part #is DS75176BN and the data
> sheet is at http://www.national.com/ds/DS/DS75176B.pdf . However I
> cannot figure out what connections I need to make to/from this
> converter. Im not familiar with the RE, RO, DE, DI, ect.
> abbriviations that are on the data sheet, so I'm not sure what goes
> to the stamp and what goes to the modem. Can anyone please help
> me?? Thanks
>
> Jason Schuler
>
>
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