Reccomended SIP Providers

[garybautista]

We are currently testing vicidial for our call center in Tijuana, Mexico. Our Servers are located in our office in Burbank, California. The Tijuana office currently have 10 users doing outbound calls. We are running a dedicated T1 in burbank and an E1 in Mexico. I noticed that from Monday to Thursday starting at around 10am Pacific Time, the call quality degrades. Also, during Fridays the quality is just bad the whole day. Is this a SIP provider problem? Are there any SIP providers you can suggest that is cost effective and has good quality?