From: James M. Prange on
dot wrote:
> On Sat, 21 Apr 2007 16:11:33 -0400, "James M. Prange"
> <jmprange(a)i-is.com> wrote:
>
>> Just make yourself a cable with a "USB 4-pin mini-B" connector on
>> each end, with the ground pins connected straight through, each
>> calculator's transmit pin connected to the other's receive pin,
>> and the battery+ pin left unconnected.
>
> You say that as though it were easy. Good luck trying to just "find"
> a USB flat 4-pin connector that is compatible with the hp50g form
> factor. Then *if* you do find one, you aren't likely to be able to
> make yourself a cable by putting those connectors on each end.

Yes, attaching those little itty-bitty connectors to a cable would
be very tricky. So get a pair of cables with the required
connector already attached to one end, cut the unwanted connectors
off of the other ends, and splice the wires together as needed.

Better yet, get a cable with the desired connectors on both ends,
check how the pins are connected, and if needed (as seems very
likely), cut the cable and splice the wires as needed.

> In the Portland, Or. metropolitan area, I have checked several sources
> and the closest suitable connector to be found was a USB type A to
> flat 4 adaptor in a kit of various adaptors selling for $30 at Fry's.
> If you ask for a "USB 4 pin mini-B" connectorized cable, you will soon
> discover that the form factor won't be compatible with the hp50g.
>
> I checked electronics stores, camera stores, and the so-called big box
> consumer electronics outlets (Best Buy, Circuit City, et al).

Try a search on eBay; a cable with the required connector on at
least one end isn't all that difficult to find, and usually a lot
cheaper as well.

That said, a "4-pin mini-B" connector isn't defined by the USB
Implementers Forum. Any such connectors are "captive", that is,
implemented for specific devices, and there seem to be more than
one design of them available, so be sure that you see a good
picture of the connector before buying a cable.

> I *wish* it were as simple as you make it sound. I have a bag full of
> ST3232 chips, all the misc components and Tiwags schematic all set to
> go! Now if I could just lay my hands on those compatible connectors!

Will you be offering the cable/converter for sale when you get it
working?

> In the meantime, I bought the Samson Cables version, which doesn't
> seem to work at 2400 Baud, yet it does work at 4800 Baud (using Conn4x
> with the PC). I really need 1200 Baud but it's not supported and ....
> oh well.

Maybe try it with HPComm or HyperTerminal at 2400bps?

--
Regards,
James

From: dot on
On Sat, 21 Apr 2007 20:04:09 -0400, "James M. Prange"
<jmprange(a)i-is.com> wrote:

>
>Will you be offering the cable/converter for sale when you get it
>working?

No. This is just for a hobby level project, but I ordered them from
Newark Electronics, and the minimum billing meant I got more than I
really needed. Who knows what I'll do with the rest of them,
especially if the cable with the so called mini-B proves too elusive.
>
>> In the meantime, I bought the Samson Cables version, which doesn't
>> seem to work at 2400 Baud, yet it does work at 4800 Baud (using Conn4x
>> with the PC). I really need 1200 Baud but it's not supported and ....
>> oh well.
>
>Maybe try it with HPComm or HyperTerminal at 2400bps?

Good idea with the HyperTerminal. I'll try that and see what happens.

-Dot-

From: electronguy on
> > In the meantime, I bought the Samson Cables version, which doesn't
> > seem to work at 2400 Baud, yet it does work at 4800 Baud (using Conn4x
> > with the PC). I really need 1200 Baud but it's not supported and ....
> > oh well.
>
> Maybe try it with HPComm or HyperTerminal at 2400bps?

Hello, I have been successful in getting my Samson cable to work with
HyperTerminal at 2400 baud. HOWEVER, I don't use the built-in XModem
from the I/O menu--it doesn't seem to work. Everything works fine if
I use the XSend command from the IOMan library (available from www.hpcalc.org).

Jim D. explained the power up/down configuration and I can see how I
can connect to my Fluke gear. I bought a standard 9-pin DSub9MM and a
project box with a 9V battery holder. I'm going to cut the cable in
half and power the RTS side of the Fluke cable with +9V (through a
current-limit resistor and power switch). DTR will be shorted to
ground (the interfacing guide available online said this was okay if a
negative voltage is not available). I will see if it provides the
correct mark voltage (<-3V) in this configuration (i.e., without
having a negative voltage on DTR). I'll use a similar approach when I
want half-duplex bit-banging (that is, I'll just provide a bias
voltage to the unused Tx pin). The cable is really quite nice :)

From: dot on
On 21 Apr 2007 17:39:05 -0700, electronguy
<electronguy(a)blueelectronlabs.com> wrote:

>> > In the meantime, I bought the Samson Cables version, which doesn't
>> > seem to work at 2400 Baud, yet it does work at 4800 Baud (using Conn4x
>> > with the PC). I really need 1200 Baud but it's not supported and ....
>> > oh well.
>>
>> Maybe try it with HPComm or HyperTerminal at 2400bps?
>
>Hello, I have been successful in getting my Samson cable to work with
>HyperTerminal at 2400 baud. HOWEVER, I don't use the built-in XModem
>from the I/O menu--it doesn't seem to work. Everything works fine if
>I use the XSend command from the IOMan library (available from www.hpcalc.org).
>
>Jim D. explained the power up/down configuration and I can see how I
>can connect to my Fluke gear. I bought a standard 9-pin DSub9MM and a
>project box with a 9V battery holder. I'm going to cut the cable in
>half and power the RTS side of the Fluke cable with +9V (through a
>current-limit resistor and power switch). DTR will be shorted to
>ground (the interfacing guide available online said this was okay if a
>negative voltage is not available). I will see if it provides the
>correct mark voltage (<-3V) in this configuration (i.e., without
>having a negative voltage on DTR). I'll use a similar approach when I
>want half-duplex bit-banging (that is, I'll just provide a bias
>voltage to the unused Tx pin). The cable is really quite nice :)

Thanks for the above info. I just d/l'd IOMAN and I'll see what I can
learn. I was using XMODEM-SERVER via the CONNECT feature of Conn4x.
It worked fine at 4800 but not at all on 2400. I think I read that
someone else was able to connect at 2400. It may be a parameter
setting or something that prevents the 2400 baud from working. I'll
try to get smarter about that tomorrow.

-Dot-

From: mk on
On Apr 21, 3:46 pm, dot <d...(a)dot.com> wrote:
> In the Portland, Or. metropolitan area, I have checked several sources..

Hi Dot,

I'm also in the Portland area too (Beaverton). Have you tried PCH
cables (http://store.pchcables.com/) in Hillsboro? Pat is a really
knowledgeable and said he had a kit with interchangeable ends - one
being the 50G connector but with two notches instead of one (I had
previously sent him a photo of the 50G connector ports and this was
his response). I didn't buy one because I stumbled across a USB cable
with the correct "mini-B" end (at a thrift store) and ended up making
my own 50G cable (photos of the cable posted in another thread).

mk