My hand is hurting because of too much stripping cables
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!
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.
Joined: 26 Jan 2008 Posts: 13049 Location: Behind The Reset Button
Posted: Tue Jun 29, 2010 20:22 Post subject:
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. _________________ [Moderator Deleted]
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.
Joined: 26 Jan 2008 Posts: 13049 Location: Behind The Reset Button
Posted: Tue Jun 29, 2010 22:06 Post subject:
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. _________________ [Moderator Deleted]
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?
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.
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) _________________ Read the forum announcements thoroughly! Be cautious if you're inexperienced.
Available for paid consulting. (Don't PM about complicated setups otherwise)
Looking for bricks and spare routers to expand my collection. (not interested in G spec models)
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??
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. _________________ Kernel panic: Aiee, killing interrupt handler!
Joined: 26 Jan 2008 Posts: 13049 Location: Behind The Reset Button
Posted: Fri Aug 20, 2010 15:27 Post subject:
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. _________________ [Moderator Deleted]