Routers with serial port inside WAN port

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fggs
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PostPosted: Sat Jun 26, 2010 1:19    Post subject: Reply with quote
My hand is hurting because of too much stripping cables Laughing

I'm using RJ45 connector because I saw a picture with it, I'm thinking about use the connector but without gluing ribbon cable. I put the cable there and use the connector to make ribbon cable steady.

Thanks for all your help, I will be the master of ribbon cable within no time! Laughing
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fggs
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PostPosted: Sat Jun 26, 2010 2:49    Post subject: Reply with quote
Yay! I did it!

I used phuzi0n's tip and didn't glueded the cable to the connector, used it just to make the cable steady. First I put the cable there, then the connector to hold.

One question: I measured the 3,3V and it gave 3,16V, is it normal? I always thought it would give a bit more than 3,3V, not the opposite.

Anyway, thanks phuzi0n, thanks barryware, I'm one step further to make my "cheap bricked router" back to life.
fggs
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PostPosted: Tue Jun 29, 2010 20:03    Post subject: Reply with quote
Can somebody measure the pins with a multimeter?

I have a few measures and I want to check:

1) RX to Ground: 3,3V
2) TX to Ground: 3,3V
3) 3,3V to Ground: 3,3V

Resistance 440~1200ohms between the pins.

If someone has an osciloscope please see if router keeps sending data from TX or just one pulse.
barryware
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PostPosted: Tue Jun 29, 2010 20:22    Post subject: Reply with quote
fggs wrote:
Can somebody measure the pins with a multimeter?

I have a few measures and I want to check:

1) RX to Ground: 3,3V
2) TX to Ground: 3,3V
3) 3,3V to Ground: 3,3V

Resistance 440~1200ohms between the pins.

If someone has an osciloscope please see if router keeps sending data from TX or just one pulse.


r u having problems?

I ask cuz I received a 3000 to repair. The serial port ohms out but the voltage in rx is high. rx seems like it is always lower than tx. (2.1 vs 3.3) but this router, vcc, rx & tx are all 3.3v.

Long story short... the serial port(s) are dead. Both inside & outside the router.

The owner stated he tried to do it himself and may have used conductors too large and may have shorted vcc to tx.

Sooooo.. the router is dead. No way to recover. I bring this up cuz it is imperative that the connections be checked for shorts and / or opens before power is applied to the router. Shorts between tx & rx won't hurt. I don't think rx to ground will hurt. Vcc to tx is bad.

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fggs
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PostPosted: Tue Jun 29, 2010 21:06    Post subject: Reply with quote
I can't say for sure. Do you have a router with working serial for you to measure for me? Just serial pins, disconnected from TTL adapter. I want voltage measurements and resistance too if possible for you, between all the pins. Do you have an osciloscope? I want to see if it send data all the time or just on boot. Both TX and RX lines from router are quiet, but "high". I think you can see it sending with a multimeter connected to TX and GND, you should see voltage levels, going up and down. Please help me :(

If you know anything about how to check if a serial port is dead, please say.

I made my TTL adapter myself, following this schematic: http://picprojects.org.uk/projects/simpleSIO/SimpleRS232.pdf

Test it if you want, seems really simple.
barryware
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PostPosted: Tue Jun 29, 2010 22:06    Post subject: Reply with quote
Ohms to ground on a working serial:

vcc = 314
tx - 1.4meg
rx = 1.5meg

voltage:

vcc 3.36
tx = 3.35
rx = 3.31

Non Working E3000.. ohms to ground

vcc = 1.04k
tx = 2.4meg
rx = 2.74meg

And... watching serial fly by working with the different routers (mostly linksys), all output stops after boot (unless you hit the enter key), then it is just like a telnet session.

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fggs
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PostPosted: Tue Jun 29, 2010 22:18    Post subject: Reply with quote
Do you know how long it takes to boot aproximally?

Thanks for your measurements, mine looks the same, so it should be working. I did a really good "serial wan" cable today, but watching with an osciloscope, TX and RX was just "high", like the router not sending anything..

I think the CFE is fine because LAN ports are responsive.

PS: Voltages of non working E3000? Sorry for asking too much..

Did you take a look at serial to TTL schematic? What do you think?
barryware
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PostPosted: Tue Jun 29, 2010 22:26    Post subject: Reply with quote
fggs wrote:
Do you know how long it takes to boot aproximally?

PS: Voltages of non working E3000? Sorry for asking too much..

Did you take a look at serial to TTL schematic? What do you think?


If the router is bricked.. it will probably keep repeating the last command or it will stop at starting program at 0x~

Don't think you PIC to rs232 is the same as a ttl to rs232 but I am sorta guessing..

All the home brew ttl adapters I have seen use some sort of max232 chip.. something like that. I bought mine for a few bucks.

I'm not so sure you can use a scope for logic circuits..

I'll be back with the voltages from the non working 3000 but I think they were all the same @ 3.3~v
fggs
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PostPosted: Tue Jun 29, 2010 22:33    Post subject: Reply with quote
From what I've studied, you need the same voltage from host (computer) and client (router). If router gives 3,3V, you need to use an adapter that uses 3,3V and NOT 5V. Just for information, max232 IC is 5V, so you rather need max3223 or similar that works from 3V to 5V.

I almost tried a max232 until I was stopped by a friend that is electric engineer: "If your router is 3,3V don't use this IC or you will burn your router's serial."

I've learned a lot with this bricked router, you were right about that.
phuzi0n
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PostPosted: Tue Jun 29, 2010 22:36    Post subject: Reply with quote
Try not to deviate offtopic too much. There's plenty of more general threads about serial and you can start your own if you like. This one is about the WAN port serial pads specifically.

(mostly @Phonism)

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veekaydee
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PostPosted: Mon Aug 16, 2010 5:12    Post subject: Reply with quote
Can not find the cable with driver at all. spent 4 hours going from shop to other in the computer market.
Found a usb audio cable which gives usb voltage at 3.3 ~3.5 v. but alas!!! no driver with it. Don't know what to do? this cable's pid and vid

usb\vid_0000 & pid_0000 \5 & 8f113f9 & 0&1

did little bit of consultation with uncle google but no joy~! Will try again today at some other shops and let us see if any luck.. Any advice how to modify a usb serial driver? Have a usb to serial port lying but how to manage that? Any idea??
LOM
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PostPosted: Mon Aug 16, 2010 6:57    Post subject: Reply with quote
vid and pid of all zero is strange, something wrong.
You can not use the USB to serial cable that you normally find in a computer shop because that is USB to RS-232 which works on + amd - 12V levels.
Your best bet is a mobile phone stall of the kind that sells 3rd party accessories, they usually have the CA-42 cable.

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zoran
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PostPosted: Thu Aug 19, 2010 16:12    Post subject: Reply with quote
veekaydee wrote:
Guru, both the cables, if attached to nokia phone load the driver and I can work with nokia phones... any clue if this can be used to load driver?


Better to question: how to connect ca-42 to the self-made
cable on the very first post? Forget about driver.
barryware
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Joined: 26 Jan 2008
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PostPosted: Fri Aug 20, 2010 15:27    Post subject: Reply with quote
I use jumper wires with alligator clips on both ends to connect my little wan port cable to the pins I soldered to the serial adapter wires. I have the exposed wires of the ribbon cable tinned.

If I use the serial adapter with a pcb that has provisions for a pin header, then I use jumpers with a female socket on each end to engage the pins.

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slimey
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PostPosted: Sun Oct 17, 2010 8:10    Post subject: Reply with quote
ugly as sin but it works

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