Both Enge Honeycomb and HKS drift chambers use the same amplifier-discriminators,
Nanometric Systems Inc. N277-L cards. Each card contains 16 channels,
and the cards are directly mounted on the two sides of the chambers. This card
requires 
5 V (0.4/0.7 A per card) powers and a threshold voltage.
Therefore two sets of low voltage power
supplies are needed to operate the chambers for Enge and HKS separately. The
5 V PS will be located in the detector huts to minimize the voltage drop,
while the threshold voltages will be provided in the electronics room of
the counting house to control discrimination levels from outside.
A total of 200 cards were purchased by Hampton University. The HKS chamber needs 80 of them, and the Enge honeycomb chamber does 70; the remaining cards are spares.
Converted to the logic signals (ECL) by N277 amp-discriminator cards, the timing information of both chamber systems will be recorded by multi-hit TDCs which are commonly used in the standard Hall-C DAQ. One Fastbus crate and 14 TDC modules (96 ch/module) are needed in each detector hut. The existing fast Fastbus crates and LeCroy 1877 models (500 ps/bin) are sufficient to run the experiment.
Due to termination of the production of Fastbus models and crates by LeCroy, a new VME based multi-hit TDC model (F1-TDC; high-resolution mode 60 ps, low-resolution mode 120 ps/bin) is under development by the Jlab Electronics Group. Though it is still at prototype stage now, it is an option to use them in low-resolution mode for drift chambers, if the new TDC can be available sufficiently before the installation of the HKS experiment.