Description: This object is meaningful only when anxt1ChanMap is set
  to ds1_modem or di_modem and should be ignored in all
  other cases. The supported protocols are:
         none(1),
         loop_start(2),
         ground_start(3),
         wink_start(4),
         immediate_start(5)
  Note: following combinations are considered valid:
   Value           InSig octet     OutSig octet
   -----           -----------     ------------
   22              loop_start      loop_start
   21              loop_start      none
   12              none            loop_start
   33              ground          ground
   31              ground          none
   13              none            ground
   44              wink            wink
   41              wink            none
   14              none            wink
   51              immediate       none
   15              none            immediate
   11              none            none
sigproto is the na/admin corresponding parameter.
This object is not valid for RA6300 only.