T200 is directly proportional to the delay expected on the ABIS link :
with terrestrial Abis, this value shall be 300ms
with satellite Abis, it shall be incremented to 1000ms (1 second)
thererfore, you can try to increase this timer until the T200 stops expiring. Basically, you should look for the root problem : what is causing such high delays on the Abis interface ? Is your link stable ? Are your LapD stable ? What about the boards that take care of LapD at BTS side (SUM or TRX) and at BSC side (TSU or TCU) ?
Is there any congestion/overload on these boards ?
Regards,
Pix