RS232 Connectors-Why oh why?!

[cfpendock]

I don't understand all this about RS232.  Where do I buy a computer with ports for RS232?  I don't think they are readily available, whereas nearly all computers have USB ports.  

On 1/17/2017 at 14:14, Davey-T said:

Don't buy a new MacBook Pro they haven't even got USB sockets 

Well, Apple sells an adapter for the new Mac for USB devices, but it doesn't sell anything for an RS232 connection.  Does this mean that not only will you need the Mac to USB connector, you will also need the USB to RS232 adapter?  I would rather use less connectors than more.

It seems to me that the only use for RS232 nowadays is the mount.  The cameras, which cost an equivalent amount, all seem to use USB.  I use an older Lakeside focuser which uses an RS232 connection, but if you buy a Lakeside focuser today, it comes with a USB connector, a modification regarded as a sales feature.

So I have to use two RS232 adapters - one for the mount and one for the focuser.  They take up space and of course their own connections are additional to all the other connections.  Both then have to have special drivers installed on the computer to make them work and to create virtual com ports on my computer - sometimes unpredictable. 

There are so many USB connected devices in the world that I cannot see them suddenly being unusable on computers.  And if they were, then I am confident that suitable adapters would become available so the devices could continue to be used.  Just like RS232.

Sadly I am not sufficiently well acquainted with computers that I can make/modify my own drivers - I am really just a user. 

It just doesn't seem sensible to produce new equipment which has to be connected via special adapters before it can be used.  

 

Chris

[Gina]

With USB being the standard for serial connection for many years now I find it strange that mounts come with a variation of the RS232 standard - 5v or 3.3v - particularly as computers these days don't have any sort of RS232 connection, so we are all virtually forced to use a sometimes dubious USB to RS232variation adapter.

[Gina]

Thinking about this a bit more, I guess mounts are generally designed to be used with their hand controllers and therefore the interface is designed to simplify and reduce cost of the combined hand controller and mount.  Plain Tx/Rx serial comms are the standard way to interconnect microprocessors.

This brings me to another point.  When controlling the mount with a microprocessor such as the Raspberry Pi rather than computer/laptop, it would seem logical to me to use the GPIO serial to connect the mount rather than a USB port then a USB to RS232variant adapter.  Why convert internal serial to USB then convert back to internal serial to control the mount?  Recent Skywatcher mounts use 3.3v logic which matches the RPi GPIO - I haven't looked at other makes.  Has anyone done this?

[Marci]

Yup, me. Works fine. Serial RS232 is serial RS232 regardless of the transport. A com port is a com port.

Tested with: celestron nexstar 4 handset, synscan 4 handset, Sony visca Ptz cameras, Panasonic video editing consoles, lg TVs, various hdmi matrix switchers, various models of projector.

Never had any issues. Have been contemplating fitting a Pi (with 12:5v dc buck) INTO an NEQ6 Pro, hardwired, and adding a breakout socket to the plate for wifi antennae / USB / cat5 - Easy if you don't need to use polarscope / have a pole master / use drift or darv.

[Gina]

Cheers Marci Do you use GPIO serial with INDI?  If so, which driver or did you write your own?

[Gina]

Another question for you @Marci - do you use Raspbian or Ubuntu Mate as RPi OS, or something else?

[Davey-T]

At least RS232 is so old nobody fiddles with it, Apple for one keep messing with the inner workings of USB  every time they do an upgrade, just to keep programmers on their toes I guess 

Dave

[Stub Mandrel]

Using RS232 is just ridiculous these days. RS232 is a wonderful robust standard to implement on resource challenged microprocessors but irrelevant for computers.

As 99.9% of users will need a USB-RS232 bridge lead any possibly advantage of RS232 is negated anyway. The manufacturers are just being lazy and cheapskate by not including a cheap and cheerful chip in their equipment that would do everything and work with their existing firmware. Or they have piles of legacy boards piled up they want to shift before they update the design.

[Marci]

14 hours ago, Gina said:

Another question for you @Marci - do you use Raspbian or Ubuntu Mate as RPi OS, or something else?

Raspbian...

[Marci]

12 hours ago, Stub Mandrel said:

Using RS232 is just ridiculous these days. RS232 is a wonderful robust standard to implement on resource challenged microprocessors but irrelevant for computers.

As 99.9% of users will need a USB-RS232 bridge lead any possibly advantage of RS232 is negated anyway. The manufacturers are just being lazy and cheapskate by not including a cheap and cheerful chip in their equipment that would do everything and work with their existing firmware. Or they have piles of legacy boards piled up they want to shift before they update the design.

Or they don't want to inflate price via licensing fees to guarantee multi-platform compatibility and continuous driver development when it's cheaper to stick with the fee-less driverless timeless industry standard and let enduser buy an adapter as necessary.

More to it than what we perceive...

[alanjgreen]

Celestron has just started shipping handsets with USB outputs. New starsense HC have USB port on the bottom. This seems to have changed the dimensions of the hand controller.

Now the HC is no longer compatible size wise with the cradle they supply with the CPC scopes so you can't use the cradle

[Gina]

14 minutes ago, Marci said:

Raspbian...

Thanks Marci   Also, which INDI driver do you use for serial GPIO?

[Marci]

22 hours ago, Gina said:

Cheers Marci Do you use GPIO serial with INDI?  If so, which driver or did you write your own?

I use the regular indi driver for the hardware ATTACHED to it, pointing to /dev/serial0... rather than /dev/ttyUSB[n] 

No need for a driver for the serial port itself... same as there being no INDI driver for USB>RS232 adapter (as the OS abstracts it to /dev/ttyUSB[n], or whatever you choose to statically call it via udev rules), just the device attached to the adapter.

Akin to their being no ASCOM driver for COM ports under windows - just the device attached to that com port. The com port itself (whether real, USB, virtual or otherwise) is dealt with pre-ASCOM.

[Marci]

@Gina - expanded the above with an edit or two!

[RayD]

On 17/01/2017 at 14:14, Davey-T said:

RS232 is a standardised system easily diagnosed unlike USB  which languished around unloved for years before becoming flavour of the month and is prey to all manner of conflicts.

Don't buy a new MacBook Pro they haven't even got USB sockets 

Dave

They do Dave, but this just highlights the fact that USB is not the "universal" one size fits all people often see it as.  Apple and some others (Samsung) are now using the "new" USB-C format, which is smaller and faster, and allows charging and data in and out on any port.  However..........when I got my new MacBook Pro, guess what the first thing I had to do was?  Yep, buy a USB-C to USB-A adaptor so I could use all my existing USB stuff!!

As noted previously RS232 (and RS485) just work as they've been used for years and are very stable, and is exactly why the are still widely used in heavy industry and critical applications.  My point is that switching to USB doesn't mean that's it....it's just it for now, until something else or some other plug format comes along.

[Marci]

At the end of the day, USB(1/1.1/2/3/C), FireWire(400/800), Thunderbolt(1/2/3)... they're all serial transports. If you stick to the common basic denominator (serial RS232) it's easy to get an adapter. Stray from that common denominator and things get more complex. It's (technically) easy to convert any of the above to serial RS232, but not easy to convert (for instance) FireWire to USB, or USB to thunderbolt, or any of the myriad sub cases (usb1 to firewire800, usb1 to usb3). Using RS232 keeps it simple as universally as possible.

[Stub Mandrel]

6 hours ago, Marci said:

Or they don't want to inflate price via licensing fees to guarantee multi-platform compatibility and continuous driver development when it's cheaper to stick with the fee-less driverless timeless industry standard and let enduser buy an adapter as necessary.

More to it than what we perceive...

If they use FTDI chips then there are no problems for drivers because these are in about 80% of non-computer USB devices anyway, an they don't need to do any driver development

[kirkster501]

Some car interfaces use it still.  As do some console ports on telecoms equipment such as routers and multiplexers.  it is live and well still, rest assured!  It is robust and reliable and the UART chip that drives it is filed tested for decades.  It just works.

[JonC]

I work in industrial gas analysis, our kit is used all around the world to analyse anything from the CO2 in coke, to the purity of gas gases used in the semiconductor industry. Our analysers do have USB, its used to connect a keyboard, or usb stick. RS232 is the current standard for interfacing equipment, most kit is still built with mA outputs to interface with stuff that predates RS232, these functions are often tested by customers so that the analysers work with their control systems. We still get requests to add extra functions that can be triggered via RS232.

I have also just looked at the specification of one of the newest AMD motherboards, hidden amongst the headers is a serial port header.

[StevieDvd]

14 hours ago, JonC said:

I have also just looked at the specification of one of the newest AMD motherboards, hidden amongst the headers is a serial port header.

As I have mentioned before on the forum ( a few times) a lot of people probably have a good old standard, driverless, com port on their motherboard just needing a header plate for around £2 to get the com port on their desktop machine.

[Stub Mandrel]

2 hours ago, StevieDvd said:

As I have mentioned before on the forum ( a few times) a lot of people probably have a good old standard, driverless, com port on their motherboard just needing a header plate for around £2 to get the com port on their desktop machine.

:-(

And I went to the bother or fitting a com port card!

[michael8554]

The mount makers (mostly) stick to Serial because it's reliable.

Most, but not all, PC and Laptop makers don't spec Serial ports because most, but not all, customers don't need them.

But some do still spec serial ports because there is a demand from industry - I wonder why?

Michael

[SmokeyJoe]

Personally I don't have a preference (I know far too little to understand the whys and wherefores) however manufacturers should provide a USB adapter with the mount.   Nothing more annoying than buying a new goto mount, waiting for it to arrive, opening the box to find instructions telling you to update the firmware, then having to spend more money and on a cable, not to mention the wait for it to arrive!  Is a six hundred quid plus piece of kit, is it too much to ask for a cable that probably cost a couple of quid to put together!!!!! This post would be full of expletives if they were aloud.  Not happy!!!!

[Stub Mandrel]

8 hours ago, michael8554 said:

The mount makers (mostly) stick to Serial because it's reliable.

Most, but not all, PC and Laptop makers don't spec Serial ports because most, but not all, customers don't need them.

But some do still spec serial ports because there is a demand from industry - I wonder why?

Michael

Legacy gear and RS232 has greater range than USB. You can also interface it using RS422 converter and send signals a mile in noisy conditions - rarely a requirement for domestic equipment.

[Stub Mandrel]

7 hours ago, SmokeyJoe said:

 Is a six hundred quid plus piece of kit, is it too much to ask for a cable that probably cost a couple of quid to put together!!!!! This post would be full of expletives if they were aloud.  Not happy!!!!

Standard Apple marketing.

My Daughter got an iPhone 7, they make a big fuss about how last-century wires on headphones are. Result.. either pay a king's ransom for their wireless headphones (which have to be regularly charged), use the supplied (wired) headphones plugged into the charging socket (so you have to unplug them while the phone is charging) or buy an expensive adapter to use the headphones of your choice.

They are so convinced that Apple Way is the One True Way they have become totally oblivious to the needs of real users.