Pinging a Wifi print server

[mwtse]

I have a WL-500gx (2 USB port version) worked in AP mode.

I am trying to add a parallel port print server into the network. The print server is Planet FPS-1100DG (direct attached to printer port with lan/Wifi).

If the printer server is connected to WL-500gx via lan cable, it works fine (both wired and Wifi clients can print). However, if I turn on the Wifi of the Planet print server, the Wifi clients cannot ping the print server using the following command:
ping 192.168.1.250 (the fixed ip address set by me, I use the same address for both Wifi and lan port)

The Wifi connection is OK (as can be found from the Asus Status page) and I can connect to the setup page (web based setup) of the Planet by a client that connected to 500gx via a lan cable.

That is to say, the print server cannot be connected by a wireless client if the print server itself is connected via Wifi. But can be reached if any or both of them is connected with lan cable.

I have not change too many setting of the 500gx, so basically all the config is the default. The print server has two modes, one is "ad hoc" (the manual said it is for peer-to-peer) and the other "infrastructure" (for connecting with existing Wifi). I choose the second one.

Is the problem related to the config of 500gx? Which option should I try to modify?

Thank you for reading.

[Jean-Fabrice]

(the fixed ip address set by me, I use the same address for both Wifi and lan port)

You cannot use the same IP address for both network interface. Doing so will result in a conflict.
Setup a different IP addresses for wifi and lan interface then retry.JF

[mwtse]

You cannot use the same IP address for both network interface. Doing so will result in a conflict.
Setup a different IP addresses for wifi and lan interface then retry.JF

Thank you for your suggestion, however,

There is only one place to set IP address, so I cannot defined them differently. There should be no problem about it, because it is DESIGNed to use the same IP address. The lan port simply switch off when Wifi is enabled, i.e. Wifi and lan port could not be used at the same time, by design.

Moreover, it is unlikely to be an conflict in IP address, as I can ping the print server using a wired client when the print server join the network wirelessly.

It seems that the router do not forward the ping from a wireless client to a wireless print server (however, two wireless PCs can ping each other).