Hello

I would like to solder one or two serial ports to the WGT634U.
I know that it's possible with MAXIM 232? as described in http://gallery.nomis52.net/albums/album48/interface.png

My problem is that I only have MAXIM MAX3222CPN chips and I would like to know how to use those.
Pinout of the chip is described here: http://www.avocetsystems.com/chipdir/pi … 222cpn.txt

I found some instructions how to build RS port with but WGT634U does not have RTS and CTS signals described in the picture of the circuit, how should I connect those? Just not connect?
Circuit: http://www.waz.org.uk/gamedev/pics/dccircuit01.gif

Can I use only one MAX 3222CPN chip to build both serial ports, using connectors T1IN, T1OUT, R1IN and R1OUT for the first serial port and connectors T2IN, T2OUT,  R2IN and R2OUT for the second one?

Regards
Kimmo

To answer to myself, yes, using MAX 3222CPN works.

I have now soldered both serial ports to the router but only ttyS1 seems to work.
I had to solder header pins to the router circuitboard, there were header only for ttyS1.

Kernel only mentions that IRQ 3 is for serial:
# cat /proc/interrupts
           CPU0
  2:    4915283            MIPS  ath0, ehci_hcd, usb-ohci, usb-ohci
  3:       4482            MIPS  serial
  4:        142            MIPS  eth0
  7:     123209            MIPS  timer

ERR:          0

And the ERR: 0. But there is no IRQ 4 which should be there for ttyS0?

Any ideas, is the second serial port disabled by hardware or just something else?

Did you ever find the answer for this?  I would be interested to know as I am trying to use two serial ports with my wrt54gs as well.  In one of the mini how-to's I read that both serial ports share irq 3.

Brendin

I have both serial ports working on one of my WGTs.  It is programmed to be a "programmer", in that the tts1 interface is connected to another "factory" WGT's tts1 to program it.  I can still get a shell on tts0, but only at 9600 baud...

I have now done the serial port mod on my wrt54gs and both serial ports are available and useable.

Brendin

I was able to get both ports working in a WGT634U too.  (Using one MAX233)

You can't use any of the enhanced signalling, (CTS, RTS, DTR, DCR, etc) because these are not present on the header.

Just make sure you choose NO software or hardware flow control on whatever you connect to these ports!

So in summary, you only need 2 lines per port, RXD and TXD.  Usually, There are at least 2 input buffers and 2 output drivers on the smallest of serial converters, so this is perfect for 2 plain ports.