VIC-2FXS Maximum cable length

[asgarcia]

Does anyone know, what is the maximum length that supports a VIC-2FXS port to connect a phone, and get a useful dial tone?. I have not found that information on specs available.

[dgahm]

A VG248 FXS port has a maximum line length of 5000 feet, or loop resistance of up to 415 ohms. I suspect the VIC is similar, but could not find the exact spec.

[kninamango]

Where did you find that? i am looking for the maximum length wire to connect an vg248 and an analogue phone and i need the source of that.

what happens if i need to extend the cable for 3 o 5 kms? (about.3.5 miles..)?

thanks

[dgahm]

VG248 spec sheet

http://www.cisco.com/en/US/partner/products/hw/gatecont/ps2250/products_data_sheet09186a008007c9bb.html

[pacameron]

The answer is ... it depends. FXS ports are designed to drive a local telephone handset, but f you use low resistance (large diameter) wire, then the loop resistance drops and hence the distance can be increased. There are still issues relating to capacitance and inductance caused by the extended distances which can attenuate the signal. The other problem is that if you increase the distance, you run the risk of external signals being induced into the long wires as well as damage to the voice ports due to lightning etc ... You can always try running the long cable, but the best thing is to use a line isolator/line driver that will protect the FXS port and be able to regenerate the signal/ring voltage. Here is a suitable device -

http://www.design2000.com.au/products/line_isolator/LI-4302.doc