serial communication with modem conflict

[mastermagrath]

I wonder can anyone help me. I have attached a 3G Mobile phone to my Pc via a serial usb connection. The modem is assigned to a com port and i can happily issue AT commmands to the phone via hyperterminal and cause it dial voice calls. However to set up a data call i have to use windows dial up after which i can pass packets to a remote server e.g. ping. The problem i have is in establishing simultaneous voice and packet. If i use the dial up to create a packet call i can no longer connect via hyperterminal to create a voice call, probably because the com port is now in use by th packet session. If i make a voice call with hyperterminal i can no longer create a packet call with dial up as again probably the com port is now in use by hyperterminal. Can anyone tell me if there is a way to access the com port by these two methods without getting this conflict.

Thanks in advance