So there is a dial tone, number is dialed, then 2 high pitched beeps, dead air, then busy signal.

Does this means the line is not provisioned correctly?

Clear dial tone means its connected to the C.O., 2 high pitched beeps is a error code when the system does not know how to route the calls?

Well, a little more info would be helpful.

Is this connected to a system and you have this problem dialing through the system?

Have you gone to the demarc, lifted the inside wiring from the telco pair and tested the line with a butt set?

Is the line copper?

Did this happen recently and did the line work previously without the problem?

Rcaman

Those tones don't sound like Telco but more like system error.

Like the Electrical Engineer said: "Well, a little more info would be helpful."

1. Tested by directly accessing the phone line and bypassing the phone system and same problem.
2. The phones always worked normal than just 1 day after a heavy rain, this happen.
3. This is a copper line, POTS.
4. Dialtone is from Telco.

Use your butt set to place the call in place of the Polycom.
Use your butt set to monitor the line while placing the call from the Polycom.
Those high pitched beeps do not sound like they are coming from the CO

OK, That's a little more information. Here's the deal: You need to completely isolate the telephone system from the CO line. Then with nothing else connected to the CO line, use you butt set to place a call. If the weird tones are there, you need to contact your dial tone provider. If the tones are not there, then a device on that line is causing problems.

Rcaman

Those beeps sound like the Polycom low battery alarm.