Thanks for your reply Ashish, but all the LTGs goin’ to PSTN have connected to DEC and the ECD parameter has set to INT. As far as I know DEC only use
for PSTN, but my case Mobile Station to Mobile station also produces echo, but not in all sites, only several site. Are there any issues regarding the TRAU or BSC? Can I trace the problem using K1205 tester, does anybody know how to use the tester?