ALDL Echo Test Program: Serial Cable

[85_Ciera_Rebuild]

If anyone buys one of those ALDL Cables with a serial interface, this information may be of interest, if stuff happens.

Moates has a "ALDL Echo Test Program (http://www.moates.net/index.php?cPath=33)," which tests your ALDL cable when it is not hooked into vehicle; you will have to power up the cable with 12Volts when doing this test. This is one test, another test was suggested by a person here (http://www.60degreev6.com/showpost.php?p=347776&postcount=2) using Hyperterminal program in Windows.

Since the ALDL Cable I bought was defective via confirmation on two different computers, I had to have a way to test both computers to see if Com1 was working.

From years ago, I bought a "null-modem serial cable," which is/was normally used to hookup two Win Computers (95/98/etc) together for transferring files.

So, I found this website, How to Do a Serial Loopback Test (http://zone.ni.com/devzone/cda/tut/p/id/3450), which explains how on RS-232 DB-9 Connector that pins 2 and 3 must be short circuited to each other on this null-modem cable, and how to use/setup Hyperterminal program. (9600, 8, No parity, 1, No Flow).

What a pill, and some 8 hours wasted on a defective ALDL cable...

[LordDurock]

If anyone buys one of those ALDL Cables with a serial interface, this information may be of interest, if stuff happens.

Moates has a "ALDL Echo Test Program (http://www.moates.net/index.php?cPath=33)," which tests your ALDL cable when it is not hooked into vehicle; you will have to power up the cable with 12Volts when doing this test. This is one test, another test was suggested by a person here (http://www.60degreev6.com/showpost.php?p=347776&postcount=2) using Hyperterminal program in Windows.

Since the ALDL Cable I bought was defective via confirmation on two different computers, I had to have a way to test both computers to see if Com1 was working.

From years ago, I bought a "null-modem serial cable," which is/was normally used to hookup two Win Computers (95/98/etc) together for transferring files.

So, I found this website, How to Do a Serial Loopback Test (http://zone.ni.com/devzone/cda/tut/p/id/3450), which explains how on RS-232 DB-9 Connector that pins 2 and 3 must be short circuited to each other on this null-modem cable, and how to use/setup Hyperterminal program. (9600, 8, No parity, 1, No Flow).

What a pill, and some 8 hours wasted on a defective ALDL cable...

OMG."From years ago, I bought a "null-modem serial cable," which is/was normally used to hookup two Win Computers (95/98/etc) together for transferring files"

thats old school. like 8kbs max right.

[85_Ciera_Rebuild]

OMG."...."null-modem serial cable," which is/was normally used to hookup two Win Computers (95/98/etc) together for transferring files"

thats old school. like 8kbs max right.


An RS-232 null modem cable transfers data at the rate of 115 Kbps. (http://compnetworking.about.com/od/networkcables/g/bldefnullmodem.htm) The fastest null modem cable, based on RS-422, supports up to 450 Kbps.

Today, null modem cables are used primarily by engineers.

USB keys, Ethernet crossover cables, and general purpose network routers have effectively made the null modem cable obsolete."


Hey, let me know how you going to check your Com1 these days??? All of my Com1 stuff, except this null modem cable has become history.

[LordDurock]

what do you wnat ot check

[85_Ciera_Rebuild]

thats old school. like 8kbs max right.

PS: AT 115kbps, that's a lot faster than dialup, especially if you live out in the sticks;)

Up to 4X faster:eek:

I use satellite for internet, and my upload is sometimes slower than that.

"Old School," well there are still millions going slower these days....:eek:

[85_Ciera_Rebuild]

what do you wnat ot check

I've received an email from the company...just got to do one more of their silly checks.

They do suggest doing a Com check via this method:


Next, if your COM ports are enabled properly
and it still doesn't work, try this. Take a
paperclip, and short pins 2 and 3 of the RS-232
port together on your PC with the HyperTerminal
program open as before. While the pins are
shorted, hit any key on the keyboard. If you see
characters appearing on your screen, then your
serial port is working fine. If you don't, then your
serial port is not working, and you have
something else going on.

[LordDurock]

okay.....never dont that go grap a sierl device 9 have see if it works

[LordDurock]

PS: AT 115kbps, that's a lot faster than dialup, especially if you live out in the sticks;)

Up to 4X faster:eek:

I use satellite for internet, and my upload is sometimes slower than that.

"Old School," well there are still millions going slower these days....:eek:

in the 80's they were slow way slow.............i have 3 t1 lines running to my house. (fathers a wireless internet provider for people in the sticks) everythings slow

[85_Ciera_Rebuild]

what do you wnat ot check

Interesting, the ALDL cable appears to work on one of their tests, but fails on Moates test.

With their test, you plug into vehicle's ALDL, powerup 12V plug, turn key-switch on, then use Window's "Hyperterminal" to see if data stream is coming in...which it is...but Moates test is sending voltages to it, for a response from the transistors.

ALDL cable has a two transistor circuit...Moates test is done without cable plugged into vehicle's ALDL connector...which would suggest something is amiss with transistor circuit not firing back.

I even tried EFILive's trial program....it too can read the baud data stream (there is a test just for this), but it can not present any relevant data....I might add that their definition for 88 Beretta will not load into their program, but I tried using related motors...but no cigars. I might add that someone suggested that since this Beretta has a Digital Dash, the programming might be different (no work).

Hence, the questions are, (1) is the incoming data stream being "gargled" via defective transistor circuit, (2) have the programs I tried (for other vehicle too) got a problem, or (3) is there some config problem I'm not aware of...there's the rub, where's the problem.

Needless to say, the reseller of ALDL cable does not present a step-by-step method, so you have to master it all. My hunch is there is a defective transistor circuit...you still get the data stream...but its messed up.

[LordDurock]

Interesting, the ALDL cable appears to work on one of their tests, but fails on Moates test.

With their test, you plug into vehicle's ALDL, powerup 12V plug, turn key-switch on, then use Window's "Hyperterminal" to see if data stream is coming in...which it is...but Moates test is sending voltages to it, for a response from the transistors.

ALDL cable has a two transistor circuit...Moates test is done without cable plugged into vehicle's ALDL connector...which would suggest something is amiss with transistor circuit not firing back.

I even tried EFILive's trial program....it too can read the baud data stream (there is a test just for this), but it can not present any relevant data....I might add that their definition for 88 Beretta will not load into their program, but I tried using related motors...but no cigars. I might add that someone suggested that since this Beretta has a Digital Dash, the programming might be different (no work).

Hence, the questions are, (1) is the incoming data stream being "gargled" via defective transistor circuit, (2) have the programs I tried (for other vehicle too) got a problem, or (3) is there some config problem I'm not aware of...there's the rub, where's the problem.

Needless to say, the reseller of ALDL cable does not present a step-by-step method, so you have to master it all. My hunch is there is a defective transistor circuit...you still get the data stream...but its messed up.


idk never done this stuff but i would guess its software based

[85_Ciera_Rebuild]

but i would guess its software based

With OBD-II, since this standard was standardized, via federal government, you can buy a pocket scanner for $50.00, and it works...you should be able to get all the relevant data needed, but OEM still could have propriety data.

With OBD-I, the software must match the ECM computer used, and its program for that engine. It is possible to create a "definition" file, if you have enough time. If TurnerPro comes out with a means to convert DS files to their format used, this will increase the OBD-1 database.

I'm going to make one last attempt, and try to find another OBD-1 vehicle that is a perfect match...I have a 1986 Chevy-Caprice, and one program was suppose to work on it....but, I noticed my SES light was different when I checked it, the SES light was dimmed and quickly blinking, which is not normal. Years ago, I used GM's Tech-1 Scanner on it, and no such light behavior existed.

Again, my gut feeling is the circuit board is "bleeding over" (i.e. bad connections, etc)...the question is, how can you physically check the electrical circuit...this is not explained.

[LordDurock]

so is you car a obd-1 or 2

[85_Ciera_Rebuild]

so is you car a obd-1 or 2

Vehicles 1996 & newer are OBD-II....my 82/86 Chevies, 85 Olds, 88 Beretta are OBD-1.

The company I bought it from will take it back...so they say...they never got back in touch...if I don't hear from them in the AM, I'm going to send it back.

Either the cable is kaput, or software/configuration is the problem...I should have built the cable myself...

I'm a computer geek...and know these tests do not rule out electrical "bleed-over." Moates test suggests something is amiss...and SES light in 86 Chevy suggests something is amiss.

I don't think the people who resale this stuff know the technical side...just sales-people...reading directions.

[85_Ciera_Rebuild]

but i would guess its software based

Using that WinALDL program, and my brother-in-law's 89 GMC Pickup (5.7), it worked (inputted data), but other than Tach reading, I don't know if all the values were valid. It suggested the vehicle was moving 127 mph in the machine-shed, but I didn't notice it moving:eek:

But, the same program was suppose to work on my 86 Chevy....go figure.

I think if I have enough time, I might be able to make it work on 88 Beretta/86 Chevy.

Some of the fine points, I think are:

1. Find out which ECM # is in vehicle
2. Use Hyperterminal program to see if data stream is coming in
3. Attempt to find right software

I was not seeing the data stream coming in on my 86 Chevy, but I did see it on 88 Beretta...but the data stream pattern was different on 88 Beretta vs 89 Pickup truck.

The question is why...it may be in Windows config settings...I don't have the time now to reset/reboot different Com1 config values...but I have this gut feeling here's where a problem might lie.

I need to find out more info...but my gut feeling is the vehicle's stream is being fed to laptop computer, and if laptop's Com1 is not in sync (or gets off-sync), there goes the data stream, bye-bye.

As I may have noted, even EFI's program could read data stream on 88 Beretta...but it could not read data stream on 89 Pickup....hmmm.

Yes, configuration is the key....but so far, it appears that "mum" is the word on this topic...I have not seen yet anybody lay down the specific config setup for Com1...other than baud rate.