Hello Chonmapat,
We do have a couple of options. If the customer would like to be able to control the scanners remotely, the system requires a tower PC with a full PCI slot, which today are hard to find. Also, if they would like to record the audio, the PC would also have to be running Windows XP, also hard to find.
We do have a web-based listening system that records the audio but it the user cannot control the scanner, although with the correct number of scanners you will receive close to 100% of the transmissions regardless unless there is a major event in which all the frequencies are being used. This solution also requires a monthly (or yearly) fee for the off-site recording and use of the software.