TP - OM-2N

Compared to an original OM-2, the OM-2N has some useful new features:

1) A viewfinder LED which lights when your T series flash is charged, and blinks when a flash exposure has been completed.
2) An updated main circuit & "P" board which automatically limits battery drain (if the mirror locks ups) to 3.5 minutes. If the mirror locks in the original 2, and it is left that way the batteries will go dead.
3) The 2N has added a 'reset' function to the meter switch. You can 'reset' the shutter by turning the meter switch to the 'battery check' position OR turning the front shutter speed dial to B.
4) The 2N has a redesigned wind lever and rewind release knob, both with a new contour. IMO, new contour of rewind release knob is difficult to turn.

Okay, so you might be thinking that, if this new fangled 'P' circuit terminates
battery drain, it might also control low light time exposures?
Right! While the 2N instruction book lists the long exposure
limit at 2 minutes, you can realistically achieve 3.5 minute
exposures, with any asa film. The OM-2 exposure limit is completely asa
based. The lower the asa of the film, the longer the capability of the camera in low light. As mentioned before, the plain OM-2 at asa 12, low light exposure capability is approx.19 minutes (approx.) and asa 1600 is 19 SECONDS. Low light capability is unlimited if you are using the mechanical B setting.

This circuit (located in the bottom of the 2N body) is sometimes
referred to as the "P" circuit (ZC1792, NLA), also controls TTL
flash exposure. Original OM-2 TTL flash: If there is insufficient flash
output, the shutter stays open, creating streaking. At times this can be used to creative ends. The P circuit in the 2N acknowledges the TTL feedback and ends the exposure at 1/60th,
regardless of whether or not here is enough flash output. Olympus felt it was better to do that than blur the photo by leaving the shutter open. The P circuit cannot be taken out or bypassed.

Regarding the main circuit board, the 2N has essentially the same main circuit as a 2. One LED is wired differently. Either circuit can be used in either camera by changing this LED (called the 'off-limiter' LED).

Flash Shoes & TTL Conn.

Shoe 1: OM-1 and 2, Regular manual or auto (not ttl) flash control with any brand flash with a hot shoe.

Shoe 2: Plain OM-2 only, Regular manual, auto flash with any electronic flash that has a hot shoe and ttl (otf, off-the-film) flash control with Olympus QA310 flash or other dedicated flash from that era. No T flash!

Shoe 3: Plain OM-2 only, Regular manual, auto flash with any electronic flash that has a hot shoe and TTL (otf, off-the-film) flash control with any Olympus T flash (T-20, T32 etc) except T45 (separate TTL cord needed, with TTL Connector 3) or other brand which happens to be compatible. No TTL on Shoe 3 with QA300 or 310 Olympus flash.

Shoe 4: OM-1N & 2N only. Regular manual & auto flash with any flash, and TTL (otf, off the film) flash control on 2N with T series flash or other dedicated flash of that era.

TTL Connector 3: OM-2 only, regular manual, auto and ttl (otf, off-the-film) flash control with any Olympus T flash that has the mating socket. T-20 has no socket and must be used with the hard-to-find TTL Connector T20. TTL Conn. 3 uses extension TTL Sync cords for off-camera flash use of T series or other brand compatible. Cords come in several lengths. Up to 9 Olympus T flashes can be wired in unison. 300 & 310 flashes are completely incompatible with the T flash system.
TTL Shoe Cord 0.6m: regular manual, auto and ttl (otf, off-the-film) off the camera flash control. This item slips into Shoe 3 or 4. Has a coiled cord which stretches to a length of 0.6 meters. While connected to a T series flash, it can be used on any camera hot shoe for regular auto or manual flash control.