On Tue, 1 Oct 2002, Yuri de Groot wrote: ... > Country Modems - a special kind of modem for poor quality rural > phone lines. ... > As I was talking to the customer, I heard a constant buzz on the > line and a clicking noise, that the customer said was from the > electric fence. ...
Hi Yuri, Well, while there are definitely differences in the quality of the analogue (phone line) side of different modems, and also admitting that there may be differences in the speed negotiation from one modem to another, it may not be the optimum way to use the speed negotiation instead of having the line fixed. There are standards defining the acceptable attenuation, crosstalk, and noise (and delay, but this does not matter here) for telephone connections. If an electric fence makes audible noise on the phone, either the fence does not conform with EMI standards, or it is too close to the phone line. If it is not standard-conformant, complain to the fence manufacturer, or put some filter on the fence to ground the emissions. If it is too close / parallel to the phone line, move either one of them. If the fence is all right, get Telecom to repair the phone line. This is all a bit more complicated than just buying a new modem, but the problem with a new modem is that noise and attenuation on the phone line reduce the bandwidth (technical term is channel capacity) you can get over it. This said, there are some tricks to deal with bad lines. On some modems you can set the transmit power. If you are not sure about the signal levels of your modem and your line quality there is a nice toll-free service offered by Telecom called FaxRight. You send a fax with your modem to 0800-108208, and they automatically send you back a fax with a measurement protocol of the transmission, including an equalization graph for the whole phone bandwidth. From this you will not know if it is your modem or the line, but if you move the modem to another (better!) location you can compare and thus exclude either of them as fault source. If it is the modem you will have to read the manual with the AT commands and find the right command and register to adjust it - if possible (on my modem you can adjust it, but others may not offer this option). Hope this helps, Helmut. +----------------+ | Helmut Walle | | [EMAIL PROTECTED] | +----------------+
