Geo-Marine Consult

Hi all!

I have something totally different from my normal (?) stuff: The telephone bills that my children generate are almost a quadratic function of their age. Since Papa pays and most of the calls are from the mobiles to some landline number I thought I try to revive my old ISDN-telephone Exchange and supply the kids with their individual (landline) numbers and telephone apparatus. Trouble is, the ISDN box is at least 10 years old (when 64k bits/s were awesome) and I couldn’t really find much on it on the web. Also, in those days I used to program it over an RS-232 using a small utility on Windows (98?). Now the box next to it is the Family-Server, and that is based on a Linux distro. No utility to run under Linux. Ok, no problem, all programming can be done with the internal phone No 1. So, get the manual, type in the codes and the MSNs (the way I did it when ISDN was hot), and: Yes, I can dial out, but incoming calls run dead. Mmmh. Says some smart arse on a forum that you have to put in the MSN without the local dialling prefix: tried that, didn’t work. Didnt’ work with local prefix either. Until I studied the DSL routers box menus (O2 Surf & Call, with VOIP) and came across a tiny note saying that the VOIP SIP numbers are only passed to the ISDN equipment as MSNs (so in other words: Pseudo MSNs), and from that information I deduced that all old rules regarding the formatting of MSNs don’t apply. Now, here is the way to make it work (from internal phone No 1):

1. Assign any one of your 4 SIP numbers to any one of five memories in the ISDN box like this:
*02149301234567# – *02 is the code to assign MSNs, the following 1 is the memory location, where to store it, and now type in the country code (49) followed by the regional code WITHOUT the leading 0 (30), followed by any one of the numbers from the list of assigned SIPs, followed by the hash (#). Put the receiver down, when you hear the internal bleep.

2. Assign any of the stored Pseudo-MSNs to the internal phones like this:
*0311# – Here, the code for assigning MSNs to real phones is *03, followed by the number of the internal phone (1), followed by the memory location of the desired MSN (1), followed by the hash (#). Put the receiver down, when you hear the internal bleep.

Hej, presto, there you go. Now, if somebody dials any of your assigned SIP numbers, it will ring on those phone(s), that you had assigned to that Pseudo-MSN. So, in short: Country code + area code + landline number make up the MSN that is required by the ISDN box.

One word of caution: The ISDN implementation in the O2 box does not entail the complete ISDN feature set. I have not really tested what works and what doesn’t, but all I needed DOES work, the telephone bills are lower (Germany flatrate for landlines), and the kids can talk until the cows come home, and there is still a way in…