Current calls placed on hold as inbound take priority

I’m using Asterisk 1.2.x and having a problem when inbound calls ware taking priority over current calls. The phones in the office are setup with a SIP account.

We have a “reception” number which is set as a variable that will call all phones in the office. If I am on a call and someone rings the number sometimes it will connect me to the inbound call and place my other call on-hold. This is quite frustrating. Does anyone have any ideas?

The phones we are using are Cisco 79XX series with 8.6 SIP firmware.

Can you post the section of your dialplan where the inbound calls go?