Hi, we have a customer site where the phones are intermittantly making a "pop" sound at the start of an incoming call and occasionally during calls too. Does anyone have any ideas about possible causes? We have tried rolling back handset firmware but not resolved. The router and cards are all new and recently installed. Router is a 2921 and handsets are SIP mainly 7821 with a couple of 7861.
Extract from sh ver:
c2900-universalk9-mz.SPA.154-3.M1.bin"
Cisco CISCO2921/K9 (revision 1.0) with 475136K/49152K bytes of memory.
Processor board ID FJC1910A274
4 Gigabit Ethernet interfaces
2 ISDN Basic Rate interfaces
2 terminal lines
1 Internal Services Module (ISM) with Services Ready Engine (SRE)
Cisco Unity Express 8.6.10 in slot/sub-slot 0/0
current handsets (we have rolled back from 10-3-1-12:
phone_firmware/78xx/kern78xx.10-2-1-12SR1-4.sbn
Thanks for any help
