Re: SERIAL PORTS (was: cannot connect gto CP3 to the SKy 6)

Christopher Erickson

Your problem isn't with the conversion of serial to USB.

Your problem is most likely with investing in box-store Chinese brand-X to
perform the conversion.

Christopher Erickson
Consulting Engineer
Summit Kinetics
Waikoloa, HI 96738

-----Original Message-----
From: ap-gto@... [mailto:ap-gto@...] On Behalf Of
Sent: Wednesday, October 17, 2012 12:36 PM
To: ap-gto@...
Subject: [ap-gto] Re: SERIAL PORTS (was: cannot connect gto CP3 to the SKy

Apparently, there are quite a few other folks that don't have a problem with
USB. All of my other devices such as main camera, guider, and focuser all
are USB. The only device I have an issue is the one developed over 50 years
ago-the serial port on the AP mount.

I understand the idea that "if it aint' broke, don't fix it." But again, I
had to buy an expensive device to convert it to USB which AP recommends on
their site to use that didn't work, and I would say that is a bigger problem
than any issue in using USB-at least for me who is now $150 poorer and with
a device that doesn't work.

Yes, I undertand the stability of RS-232. It should be, it was developed
over 50 years ago.

But when most computers and laptops sold today no longer even have serial
ports, and you have to convert the serial to USB anyway, it seems like it
may be time to catch up to the 21st century, even if it is a step backward.
How about this-put both a USB AND a RS232 port on the controller. Then you'd
have the best(and worst) of both standards and could take your pick.


--- In ap-gto@..., "Steve Norvich" <snorvich@...> wrote:

This is an absolutely wonderful post. It reinforces my decision with
to the Astro-Physics GTO1600. I was never comfortable with the
s USB oriented solution.

-------Original Message-------

From: Christopher Erickson
Date: 10/17/2012 3:19:59 PM
To: ap-gto@...
Subject: RE: [ap-gto] Re: SERIAL PORTS (was: cannot connect gto CP3 to the
SKy 6)

"Roland, are your new mounts going to stick with the old serial port
standard? I hope not."

Careful what you wish for...

Points to consider:

* For better or worse, RS-232 Serial has been the defacto-standard
denominator for decades and will likely continue to be so for decades to
come. With hardly an exception, very microcontroller made in the world
today has an RS-232 serial port cast right in its silicon. Whether you can
see them or not, RS-232 serial ports are EVERYWHERE. In fact all modern
"smart" refrigerators have hidden RS-232 serial ports that exist for the
service technicians armed with smart diagnostic tools. Even your car's
OBD-II or CANbus diagnostic interface has embedded RS-232-style serial
communications. Serial can be converted to just about anything (USB,
Ethernet, TCP/IP, Bluetooth, fiber-optic, Xbee wireless, etc.) USB can't
converted to anything without an intervening pair of computers and the
software on both ends, which usually doesn't exist. Not to mention the
expenses involved.

* RS-232 Serial can be run great distances (even thousands of kilometers)
using a great number of inexpensive media types and converters. USB can
barely make it across the average room without brain-splitting problems.

* Probably 90% of all problems with USB-Serial adapters are
related. Just about everything coming out of China has Chinese-written
drivers and these have always been incomplete and highly-problematic. In
experience, the best and most trouble-free adapters use FTDI chips.
Prolific is a distant second place and everything else is almost complete
junk for any but the most basic of applications.

* For years, iOptron has offered GOTO mounts with USB interfaces instead
serial interfaces and the unending grief experienced by their users
to USB problems is infamous. In fact iOptron's most recent GOTO mounts
gone back to serial interfaces! Good news for people with iOptron mounts
with USB interfaces is that all iOptron did was incorporate a Chinese
USB-to-Serial chip into the mount and the iOptron microcontroller has a
serial interface on it! Cutting two traces and installing a connector has
allowed users to bypass iOptron's junky serial-to-USB adapter chip and
horrible drivers.

* Having a serial interface on my mounts means I can easily control them
with a PC, wired/wireless smartphone or tablet computer. If it only had
USB, that usually eliminates the smartphone and tablet computer. SkyFi has
a wireless USB adapter (expensive) coming out that may work with some
USB-only iOptron mounts but they are already warning people that it is a
"work in progress."

* USB 1 is obsolete. USB 2 is officially obsolete. USB 3 is current but
USB 4 is right around the corner. Most USB 3 ports these days don't
USB 1 peripherals. USB 4 ports are unlikely to support USB 1 or 2
peripherals. Why would I want to spend $10-20,000 for a premium mount with
an interface that will be obsolete and unsupported in about five years?

Like I said, be careful what you wish for.

Christopher Erickson
Consulting Engineer
Summit Kinetics
Waikoloa, HI 96738


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