ISDN Troubleshooting        This is the questions page to the problems you have. Each question on this page takes you directly to the answer rather than having to scroll all the way down a full page of information.        Please bear in mind this page is updated daily and if the question you seek the answer to is not here, then it may well be here tomorrow.        Please feel free to email the author of the site if you have a specific problem you need help with and we will do what we can to get back to you and solve the issue. Don't forget to check out our tips and tricks section under your operating system. We have a lot of answers to your questions to solve you problem there also.   (Q1) Question Do routers (or whatever) [have built-in] firewalls or would I be better using Internet Connection Sharing (in XP) from my home PC and installing some firewall software? (Q2) Question Does anyone know of any company's that supply a 128K or 256k ISDN connection. I would want it unlimited without any time restrictions or extra hidden costs. (Q3) Question No ISDN devices were found. Please install an ISDN device and run the configuration wizard again. (Q4) Question I'm shooting my PC to pieces if I don't find a solution to my problem soon! When my Broadxent ADSL 7430 PCI modem tries to negotiate a connection to the remote server, it hangs up leaving me with an 'error 721' message. Everything seems OK with the modem because I've run a diagnostic and it passed everything. The win 2k drivers seem to have loaded up fine too. I think the problem lies in the correspondence between modem and server. The protocol is just not understood.  (Q5) Question Troubleshooting with the Alcatel Speedtouch 510 ADSL router (using standard configuration only) (Q6) Question Windows claims there is no dial tone? (Q7) Question I have an Alcatel USB modem but I can't login?