anchor.diff:  (<-) are in fact parsed and their values are stored by OsmoBTS, but these
   stored items are currently not used in the OsmoBTS code base.
   
  -.IEs conforming to TS 12.21
  +.IEs conforming to TS 52.021
   [options="header",cols="5%,10%,40%,5%,40%"]
   |===
  -| tag (hex) | TS 12.21 § | IE name | <-/-> | Received/Sent by OsmoBTS
  +| tag (hex) | TS 52.021 § | IE name | <-/-> | Received/Sent by OsmoBTS
   | 0x00 | 9.4.1  | Abis Channel  |  | _ignored_
   | 0x01 | 9.4.2  | Additional Info  |  | _ignored_
   | 0x02 | 9.4.3  | Additional Text  |  | _ignored_
  
positive.code: 
  
  ==== Messages Not Implemented by OsmoBTS
  .3GPP TS 12.21 messages not implemented by OsmoBTS
  [options="header",cols="10%,10%,80%"]
  |===
  | TS 12.21 § | type code (hex) | Message
  3+<| *SW Download Management Messages:*
  .3+.| 8.3.1 | 0x01 | Load Data Initiate
              | 0x02 | Load Data Initiate Ack
  
negative.code: ==== Additional Attributes and Parameters
  
  The following Information Elements are defined in addition to those
  specified in 3GPP TS 52.021 Chapter 9.4.
  
  All of these additional IEs are _received_ by OsmoBTS.
  
  These attributes are not used by OsmoBTS, but
  simply passed to OsmoPCU connected to the PCU socket.
  
  .Additional IEs handled by OsmoBTS but not defined in TS 52.021
  [options="header",cols="5%,50%,45%"]
  |===
  | tag (hex) | IE name | Description
  