The problem is between a PDA , and the 2600 integrated modems ( 8-NM module ).
The PDA is calling a PSTN number of 2600 integrated modem connected to the pstn, the router is configured to work as an X25 PAD so when the PDA is supposed to connect to the asynchronous line of the router , automatically an X28 session is opened and the PDA makes an X25 call to the x25 address of an x25 device connected to the serial line of the router.
We tried, the configuration with an external modem connected to an asynchronous serial line of the router and every thing was Ok.
When we try this configuration with the integrated modems , the message modem failed to handle the call appears in the router console and an x28 debug shows that the router after many attempts connects to modem but it sends many strange caracters than it disconnects few times after.
The external modem used in this experiment is a v32bis/v32 modem and the pda is connected with a speed of 9600 bps or 300 bps usally with no error correction.
We configured the integrated modems of the 2600 with the their at commands , we set the modulation protocol as v32bis/v32 with no error correction no MNP and no v42bis but the the same problem occured.
