--- In RoboBricks2@yahoogroups.com, Brandon Blodget <bbhome@...> wrote:
>
> Hi all,
>
> I am trying to connect the on board 3.3v serial port of the
> wrtsl54gs router to the WireHost module. I've followed the
> instruction at
>
>
http://www.hbrobotics.org/wiki/index.php5/WRTSL54GS#Using_on_board_serial_port
>
> When I try and send serial data from the wrtsl54gs using
> microcom my characters are echoed back to me but I don't
> get any other data back. For example when I type "Z<enter>"
> it echo's 'Z' and a newline but no info about the modules is
> returned. When replacing/bipassing the MAX232 do I need to
> pass through the DTR signal? When I use the usb2serial
> cable connected to the router (with the MAX232 on WireHost)
> sending commands from microcom works as expected. Any
> suggestions?

Brandon:

I have not posted a circuit the WireHost conversion.
The longer term solution is to use a newly designed
module called SerialHost1, which I am just about ready
to send off to manufacture.

The circuit I use lives in a component header that plugs
into the MAX232 socket. Here is a description:

The pins on the WRTSL54GS are 1 through 5 with pin 4
being a no-connection. In addition, pin 1 is 3.3V
which is not needed. Thus, only three wires are used:

Router Pin2 => Max232 Pin 9 (TX)
Router Pin3 => Max232 Pin 7 (RX)
Router Pin5 => Max232 pin 11 (Ground)

In addition, there is a voltage divider. I have a
330 Ohm resistor between Max232 Pins 7 and 10.
I have a 470 Ohm resistor between Max232 Pins 2 and 7.
This provides a voltage divider of .5875=(470/(470+33)).

The signal from the router comes out of router-pin3
at between 0 and 3.3V and lands on max232-pin9 which
is forwared to the TTL compliant input of the WireHost.
The WireHost response comes in on Max232-pin10 a 0 to 5V
is divided down to 0-2.93V and sent on to the router-pin2.

Is that the circuit that you have? (By the way, I'll
transfer the discription above to the wiki.)

-Wayne