facilities.md: Update ISDN section with links / clarifications

* define who "we" is in the context of the section
* hyperlinks to osmcoom wiki pages for relevant technology
* link to etherpad where interested parties can record their location
* some technical clarifications

docs/facilities.md

@@ -103,9 +103,9 @@ Heaven is the “partner exchange” of the Chaos events. We try to distribute l
 
 ## ISDN (and POTS)
 
-We are planning to operate an experimental ISDN and analog telephony network.
+We (jolly + LaF0rge) are planning to operate an experimental ISDN and analog telephony network.
 
-The subscriber lines will be terminated using de-commissioned V5_Access_Multiplexers that were donated by telecom operators together with the osmo-v5 protocol stack and osmo-cc.
+The subscriber lines will be terminated using de-commissioned [V5 Access Multiplexers](https://osmocom.org/projects/retronetworking/wiki/V5_Access_Multiplexers) that were donated by telecom operators together with the [osmo-v5](https://gitea.osmocom.org/retronetworking/osmo-v5) protocol stack and [osmo-cc](https://gitea.osmocom.org/cc).
 
 This network will be provided for people to re-enact the good old telephony days, using anything as old as rotary dial phones, up to the 1990s ISDN experience.
 
@@ -118,7 +118,7 @@ So if you still have your old wired telephones or ISDN equipment in a basement,
 We can offer
 
 * analog POTS ports, exposed as classic 2-wire “ab” interface according to German standards.
-* ISDN ports using Uk0 interface, using 4B3T according to German standards
+* ISDN BRI (basic rate interface) ports using Uk0 interface, using 4B3T according to German standards. The signalling is EDSS1 (Euro-ISDN). The configuration is PTMP (German: Mehrgeraeteanschluss), which was the default for most private ISDN lines in Germany.
 
 #### What Equipment do I need to bring?
 
@@ -132,9 +132,14 @@ In addition, it is wise to bring sufficient length of telephony wires so you can
 
 #### Where can I connect to the network?
 
-You would need to run some telephony wire (or CAT5, if that’s all you have) to one of our “points of presence”, where we will put V5_Access_Multiplexers.
+You would need to run some telephony wire (or CAT5, if that’s all you have) to one of our “points of presence”, where we will put V5_Access_Multiplexers.  On the network side, the connector is a RJ45 connector where the center two pins are used for the a/b wires.   This configuration is also compatible with plugging RJ-11/RJ-12 connectors in the RJ45 sockets.   We also have some RJ45 connectors and crimp tools if your end terminates in bare wire.
 
-We are planning to deploy those at only a few (2-3) “Datenklo” around the camp site. One of them will be in the vicinity of the PoC tent, the other locations are yet to be determined.
+We are planning to deploy those at only a few (3-4) “Datenklo” around the camp site. One of them will be in the vicinity of the PoC tent, the other locations are yet to be determined.
+
+
+#### Etherpad of people interested in getting connected
+
+**PLEASE ENTER YOURSELF IN THE [ETHERPAD](https://pad.hacksaar.de/p/CCCamp2023-ISDN) WITH YOUR LOCATION IF YOU ARE INTERESTED**
 
 #### What kind of services do you offer?