На микросхеме выводы:
A - Noninv. RD
B- Inv. RD
Y- Noninv. TD
Z- Inv. TD
А на разъеме платы MOXA CP112
для RS-422 приводят просто без названий
TxD+(B)
RxD+(B)
TxD-(A)
RxD-(A)
Посидев в википедии и почитав, что это дело запутанное решил обратится к Вам
- Pin labeling
The EIA-485 differential line consists of two pins:
A aka '−' aka TxD-/RxD- aka inverting pin
B aka '+' aka TxD+/RxD+ aka non-inverting pin
SC aka G aka reference pin
The B line is positive (compared to A) when the line is idle (i.e., data is 1).
In addition to the A and B connections, the EIA standard also specifies a third interconnection point called C, which is the common signal reference ground.
These names are all in use on various equipment, but the actual standard released by EIA only uses the names A and B. However, despite the unambiguous standard, there is much confusion about which is which:
The EIA-485 signaling specification states that signal A is the inverting or '-' pin and signal B is the non-inverting or '+' pin.[6]
This is in conflict with the A/B naming used by a number of differential transceiver manufacturers, including, among others:
Texas Instruments, as seen in their application handbook on EIA-422/485 communications (A=non-inverting, B=inverting)
Intersil, as seen in their data sheet for the ISL4489 transceiver[7]
Maxim, as seen in their data sheet for the MAX483 transceiver[8]
These manufacturers are incorrect, but their practice is in widespread use.
Therefore, care must be taken when using A/B naming.
The standard does not discuss cable shielding, but makes some recommendations on preferred methods of interconnecting the signal reference common and equipment case grounds.
Но меня посещает мысль соединить все в таком порядке:
max3488 ---------MOXA CP112
A --------- TxD+(B)
B --------- TxD-(A)
Y --------- RxD+(B)
Z --------- RxD-(A)
