Problems with WIP and FCM


I have a M1306B modem with firmware 6.57c, wip 2.00.31, and OpenAT OS 3.13.2

I have an embedded application which opens the GPRS bearer and a communication socket to a remote host. Over the socket I’m sending small amounts of data, and as long as the AT command mode is enabled, this is working quite well.

But, when I set the UART in V24 (terminal/data) state, the problems occur.

What I see is this:

  1. If I try to connect the GPRS bearer after V24 mode is enabled using the adl_fcmSwitchV24State(fcmHandle, ADL_FCM_V24_STATE_DATA); the GPRS connection fails.

  2. If I first connect the GPRS bearer, and then the socket (using the WIP API in the application) and then enables V24 mode (data mode) I’m unable to send data over the socket. I write the actual data to the socket, but the data are not written to the remote host.

If I then enables AT mode again, (ADL_FCM_V24_STATE_AT) then all the date I’ve written to the socket are sent to the remote host. So, in case 2, all data written to the socket in data mode is buffered and released / sendt when data mode is disabled. I need to send the data I get, without buffering in data mode. How can I disable the buffering that FCM does in data mode when I’m writing to the socket?


Cross-reference: … =6215#6215