The Mark4 correlation system represents stations with a single letter. Thus a 2-letter to 1-letter mapping is needed for each station. There is a default mapping (compiled in) which includes a number of stations and seven empty slots to be used as stations not in the table are encountered:
|Default Station Assignments|
|A ↔ Ai||B ↔ Bd||C ↔ Sh||D ↔ 13|
|E ↔ Wf||F ↔ Eb||G ↔ Gb||H ↔ Ho|
|I ↔ Ma||J ↔ Cc||K ↔ Kk||L ↔ xx|
|M ↔ Mc||N ↔ Ny||O ↔ Kb||P ↔ Oh|
|Q ↔ Tc||R ↔ Zc||S ↔ Nt||T ↔ Ts|
|U ↔ Ur||V ↔ Wz||W ↔ xx||X ↔ On|
|Y ↔ Yb||Z ↔ Mh||a ↔ Ap||b ↔ Br|
|c ↔ Cm||d ↔ Cn||e ↔ xx||f ↔ Fd|
|g ↔ xx||h ↔ Hn||i ↔ xx||j ↔ Jc|
|k ↔ Kp||l ↔ La||m ↔ Mk||n ↔ Nl|
|o ↔ Ov||p ↔ Pt||q ↔ Qb||r ↔ Ro|
|s ↔ Sc||t ↔ Ti||u ↔ Ur||v ↔ Pv|
|w ↔ Wb||x ↔ xx||y ↔ Y||z ↔ xx|
As each station not in the table is found, an xx entry in the table above is assigned to that station and the corresponding single letter code is used thereafter. If you have more than seven stations not in this table, or if you wish to assign the single letters that will be used for each stations, you must supply a file with new mappings and inform
difx2mark4 via an environment variable
HOPS_STATION_CODE which should be the (local or absolute) path to a file with the new one-letter ↔ two-letter pairings. E.g.
difx2mark4 enforces a one-to-one mapping, as bad things will happen if different stations were to be given the same one-letter identifier. (The hops software has no way to tell that this has happened, and
difx2mark4 does not currently have any safeguard against this.) So if you wish to reassign one of the existing assignments, you must first make it an open slot (i.e. assign it to xx) and then assign it. E.g.
will shift Kp from k to W, and install Hh in the k slot.