manual: describe TA-based positioning and cell locations

Change-Id: I3d8ae0f6fef0c60499a5e133d3dd0ebd54e8c321
diff --git a/doc/manuals/chapters/running.adoc b/doc/manuals/chapters/running.adoc
index 0a3174e..684866e 100644
--- a/doc/manuals/chapters/running.adoc
+++ b/doc/manuals/chapters/running.adoc
@@ -63,10 +63,11 @@
 ===== Configure SCCP/M3UA (AoIP)
 
 OsmoSMLC acts as client to contact an STP instance and establish an SCCP/M3UA
-link.
+link. OsmoSMLC always uses the SSN "SMLC (BSSMAP-LE)" (SSN code 252). The
+configurable point-code defaults to 0.23.6 (190).
 
 An example configuration of OsmoSMLC's Lb SCCP link, assuming the SMLC at
-point-code 1.23.6 via an SG listening for M3UA at 127.0.0.1:2905:
+point-code 1.23.6, listening for M3UA at 127.0.0.1:2905:
 
 ----
 cs7 instance 0