OTC markets - ARCA and ARCX (arca edge) are the same ECN ?

Some brokers allow orders to otc markets with ARCA

But IB send orders to ARCX

 

Edited.
I think they're basically the same thing. Originally Archipelago Exchange, hence ARCX. Then bought by NYSE, now called NYSE Arca. But it appears the ARCA means only the equities, while for options the abbreviation is PSE (probably from the days when Archipelago merged with the Pacific Stock Exchange). From IB's site:

• NYSE Arca - Equities (ARCA)
• NYSE Arca - Options (PSE)

So maybe IB uses ARCX as a catch-all for both ARCA and PSE. That's my guess.

 

Do you know which brokers route to ARCA for otc?