add bits and pieces of documentation
diff --git a/doc/BS11-OML.txt b/doc/BS11-OML.txt
new file mode 100644
index 0000000..e5c3299
--- /dev/null
+++ b/doc/BS11-OML.txt
@@ -0,0 +1,31 @@
+The Siemens BS-11 supports the following additional GSM 12.21 OML operations:
+
+
+CREATE OBJECT
+
+abis_om_fom_hdr.obj_class can be
+A3:
+A5: ALCO, BBSIG, CCLK, GPSU, LI, PA
+A8: EnvaBTSE
+A9: BPORT
+
+the abis_om_obj_inst.trx_nr field indicates the index of object, whereas the
+abis_om_fom_hdr.bts_nr indicates the type of the object.
+
+enum abis_bs11_objtype {
+ BS11_OBJ_ALCO = 0x01,
+ BS11_OBJ_BBSIG = 0x02, /* obj_class: 0,1 */
+ BS11_OBJ_TRX1 = 0x03, /* only DEACTIVATE TRX1 */
+ BS11_OBJ_CCLK = 0x04,
+ BS11_OBJ_GPSU = 0x06,
+ BS11_OBJ_LI = 0x07,
+ BS11_OBJ_PA = 0x09, /* obj_class: 0, 1*/
+};
+
+In case of CREATE ENVABTSE, the abis_om_obj_inst.trx_nr indicates the EnvaBTSEx
+number.
+
+In case of A9 (CREAETE BPORT), the abis_om_obj_inst.bts_nr indicates which BPORT
+shall be used.
+
+