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ACO32 Tech Notes

A new FORJ will not fit in the clamp on an existing ACO32 commutator


Product: ACO32, FORJ
Version: Built 2015-06-11 or later
Date Added: 2015-06-11


The ACO32 form factor is designed to support the addition of a Doric fiber-optic rotary joint (FORJ). The physical design of the DORIC part was changed slightly by the manufacturer and made it necessary to redesign the clamp that holds the FORJ in place in the ACO32.

The clamp redesign doesn't affect functionality, but it does affect how the assembly is installed in the ACO32 commutator. Previously, the FORJ was inserted from the bottom of the clamp. To accommodate a new flange on the FORJ, a small lip has been added to the clamp to keep the FORJ from slipping through. As a result, the FORJ must now be inserted from the top. If using a new FORJ with an old clamp without the lip, the FORJ won't seat correctly.


Customers ordering replacement parts will need to be aware of this difference. If you need a new clamp, contact TDT for assistance.

Building a custom headstage to use with PZ, IZ, or ACO


Product: PZ5, PZ2, PZ3, IZ2, IZ2H, IZ2M, IZ2MH, ACO32, ACO64
Version: All
Date Added: 2012-02-08


This tech note provides the information needed to wire a custom or third-party headstage to TDT amplifiers, stimulus isolators, and commutators.


The PZ5, PZ2, PZ3, IZ2, IZ2H, IZ2M, IZ2MH, ACO32, and ACO64 all use the same female mini-DB26 connectors. The mating male connector is made by TE Connectivity (previously Tyco), part number 5749621-2, and can be purchased from Newark, Digikey, or similar vendors. The part number for the connector's backshell kit is 749608-2.

The PZ5, PZ2, PZ3, IZ2, and IZ2H are all battery powered. To conserve power, each bank of channels will not turn on unless a headstage is connected. The device detects whether a headstage is connected through the HSD (HeadStage Detect) pins: pins 18 and 19. These pins should be shorted together on the headstage connector. If pins 18 and 19 are not shorted the headstage will not be detected and the bank that it is connected to will power off.


This does not apply to the IZ2M and IZ2MH. In those devices all banks are always powered.

The pins on the headstage should be made to match the connector on the intended device. The pinouts for each device are shown below.


The user must increment the channel numbers by 16 (or 8) according to the amp, mode and position of the connector. So, for the connector labeled 'A', A1 is channel 1 while on the connector labeled 'B', A1 may be channel 17.

PZ5 Connector Pinout for Building Headstages

PZ5 NeuroDigitizers have up to eight 26-pin headstage connectors on the back of the unit. The connectors are labeled alphabetically from bottom to top. Each connector carries signal for one bank of channels with ground and reference. The corresponding channel numbers depend on:

  1. the reference mode configurations

  2. the position of the bank in a logical amplifier.

For simplicity sake, the diagrams below assume channels for that connector begin with channel 1. For example, A1 - A16 represent the 16 channels coming from the connected headstage.

Local Mode

None Mode

Shared Mode

Differential Mode

PZ2 Connector Pinout for Building Headstages

PZ3 Connector Pinout for Building Headstages

IZ2, IZ2M, IZ2MH Connector Pinout for Building Headstages

IZ2H Connector Pinout for Building Headstages

The ACO passes signals from each header to the pins on the associated DB26 connector on the face of the commutator. The unused pins should not be connected. The pins on the headstage should be made to map to the connected amplifier/stimulator via the header as follows:

ACO Headers - Pinout for Building Active Headstages

For PZ2 or PZ5

For PZ3

ACO Headers - Pinout for Building Passive Headstages

For IZ2, IZ2M, or IZ2MH

For IZ2H