dave@bgtys6.uucp (Dave Hubert) (03/28/91)
Hi. I've now taken apart a mac serial cable and have connected female pins
to the wires and connected them to the 48sx port. I'm using MacKermit, but
something is amuck, like...
Where does the shield go?????????
ANYONE? ANYONE?
Mac rs232(mini 8) HP serial port
_____________ ______________
| o o o | | o o o o |
| | \|__|__|__|/
| o o o | | | | +-> SHIELD
\ ^ ^ ^ / | | +-> TX(output)
\ | o | o| / | +-> RX(input)
-|---|---|- +-> Signal GND
| | +-> RX(input)
| +-> Signal GND
+-> TX(output)
This is all labled from the 48sx's point of view. Is this right?
Another important question...
I would suppose that the wires should be connected TX to TX, RX to RX,
Signal to Signal, and SHIELD to SHIELD???
~~~~~~ ~~~~~~
Could I be wrong? ( I am not an engineer, but a mathie! )
Now, assuming that the SHIELD does not have to be connected, and that the
connections should be as above, then I should have a working cable. I have
taken some sort of ??voltometer?? and the connections of the cable are as
they should be. The cable is plugged into the modem port of the mac.
That would mean I am not using MacKermit properly. Therefore...
These are my settings:
MacKermit: baud 9600, parity none, block check type1, handshake none,
( recieve, send )
start of packet char(1, 1)
end (13, 13)
pad char (0, 0)
padding (0, 0)
seconds for timeout (30, 10)
packet length (90, 90)
48sx setup: wire, ASCII, baud 9600, parity none 0, checksum type 1,
translate code 0.
Then, following the manual, pg.623, using local/local configuration:
1. on 48sx, execute RECV
2. on MACII, send a file called "dave" under FILE menu. I am sending
a MS-word file that is saved as text only containing "dave was here!".
The 48sx and MacKermit both reply retry #1, retry #2, .... with lengthy pauses
in between and an eventual timeout error on the 48sx.
I have tried send a variable containing a string on the 48sx to the mac, with
the same response.
Any and all responses are welcome! Don't try to mail me, responses would probably
bouce almost as far as my checks do, off my net address.
Thanks,
An exasperated and disappointed...
-Dave.
NOTE: I even called HP and they said it would cost $50.55 to have them order
and mail me their serial cable, with 6-7 weeks for delivery. Sigh...madler@nntp-server.caltech.edu (Mark Adler) (03/29/91)
Don't worry about the shield line at all. In case you're not sure if
you know which end signal ground is really on, you can connect shield
to signal ground. If you are sure, just leave it unconnected.
It looks like you have it right, if you're diagram is the perspective
I think it is (you might specifiy "looking at the connector on the Mac"
or "looking at the plug"--you could also avoid ambiguity by offsetting
the pins, as they are in the real connector).
Here's some diagrams out of the HP documentation:
2.1 Cable Wiring
The pin definitions for the HP 82208A (IBM) and 82209A (Macintosh) serial
cables for the HP 48 are shown on the next page, including the 25 pin end of
the 9-25 pin adapter. All signals are labeled from the HP 48's point of view.
HP 48 I/O Cable Pinouts
______________
Macintosh end of cable | - - - |
5 -- RX (input)---|--V V-------| 4 -- Signal GND
| - - - |
| ^-|--3 TX (output)
\ - - /
----______----
PC end of cable with
9-25 adapter /------------------7 Signal GND
| /----------3 TX (output)
| | /--------2 RX (input)
13 V V V V------1 SHIELD
___________________________
\ O O O O O O O O O O O O O /
\ O O O O O O O O O O O O /
-----------------------
25 14
PC end of cable
/--------------5 Signal GND
| /----------3 RX (input)
| | /--------2 TX (output)
V V V 1
_____________
\ O O O O O /
\ O O O O /
-------
9 6
Notes:
1. Output = from HP 48 _________
s. Input = to HP48 | o o o o |
\_______/
^ ^ ^ ^
| | | \------ 1 SHIELD
| | \---------2 TX (output)
| \-----------3 RX (input)
\-------------4 Signal GND
Also, if it doesn't work, you can always try simply reversing the
transmit and receive lines. RS-232 is spec'ed so that that can't
hurt anything.
Mark Adler
madler@pooh.caltech.eduTDSTRONG%MTUS5.BITNET@VM1.NoDak.EDU (Tim Strong) (03/30/91)
Swap your TX and RX lines. That I think is the problem. As I understand it there are two types of devices when it comes to labeling lines: DTE's (Data Terminal Equipment) and DCE's (Data Communications Equipment). When one attaches a modem or a printer to a computer one is hooking a DCE to a DTE. In this case the lines are hooked up so that their names match ie TX to TX, RX to RX. The problem here is that you are hooking up two DTE's the Mac and the 48. In such cases what is needed is called a "null modem" connector. What this means is that the Send and Recieve lines are swapped inside the cable so that TX is attached to RX on the other end. If that all confuses you (sometimes I think us computer people make up jargon just to feel important), try this. Look at your diagram. Notice how youve labeled TX as output at both ends. Shouldn't the output of one machine be attached to the input of the other? So shouldn't TX be attached to RX? Also don't worry about shield. It can probably be either left unconnected or hooked to signal ground. Hope this helps? ====================================================================== ___ I__) _ _I _ _ TIM STRONG <TDSTRONG%MTUS5.BITNET@CUNYVM.EDU> I \ (_I (_I (_I I MICHIGAN TECH. HOUGHTON, MICHIGAN ======================================================================