The widely used MONARCH MPB-32 patchbay supports unbalanced signals only. All jack sockets are designed as two-pole TS sockets. If individual (or all) slots are replaced by the upgrade cards, balanced signals can also be patched or insert cables can be split. With the insert card, an unbalanced TRS insert point (e.g. from the mixing console channel) is split to two TS sockets, so that the SEND and RETURN signals are then available on two separate sockets for further processing (TRS -> 2x TS). The wiring is done according to the standard Tip=Send; Ring=Return. If an insert point is assigned differently, the card can be reversed and then the configuration Tip=Return; Ring=Send is obtained. With the TRS card, symmetrical signals can be processed in different configurations (open, half-normalled or parallel configuration). Depending on which side is facing up, the sockets on the front and back are wired in the "open" or "half-normalled" configuration. If you need the "parallel" configuration for some cards, this can be set by three solder bridges. NRJ6HF from Neutrik are used as sockets for the upgrade cards.