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3. Default mode automatically cycles through all antennas. The interrogator will freeze at a certain
antenna selection by issuing the Select Receive Antenna command.

Pins 10, 22, 9, 21, and 8 are the high order bits of the hardware pins that select the transmit antenna.
Bit 0 is kept internal to the interrogator. These lines are used to drive external multiplexers for multi-
antenna systems. They are controlled by:

1. Setting up the antenna select table in flash memory (if necessary) using Load Antenna Table
command.

2. Issue the Set Antenna Quantity command.

3. Default mode automatically cycles through all antennas. The interrogator will freeze at a certain
antenna selection by issuing the Select Transmit Antenna command.

Pins 5, 17, 4, and 16 are TTL level inputs that can be read with the Read Peripheral Inputs command.

Description

Minimum

Maximum

Input - High Level

2.0 V

VCC*

Input - Low Level

0V

0.8V

Input Signal
transition Time

-

250nS

Input Leakage
Current

-10µA

+10µA

Input Capacitance

-

10pF

*Note: VCC Min. is 4.75 volts, VCC is nominally 5.0 volts.  All voltage values are DC.

There are 8 peripheral outputs internal to the interrogator. 4 of these are available at the DB-25
connector: pins 20, 7, 19, and 6 can be controlled by setting or resetting bits, 3, 4, 5 and/or 6 of the
command data byte of the Write Peripheral Outputs command. The outputs are compatible with
CMOS levels.

Description

Minimum

Maximum

High level output
voltage @
I

OutputHigh 

= 1.0 mA,

VCC* Min.

VCC* - 0.5 Volts

-

Low level output
voltage @
I

OutputHigh 

= 12.0

mA, VCC* Min.

-

.4  Volts

Source current

-

-1.0 mA

Sink current

-

12.0 mA

Output leakage
current

-10 µA

+10 µA

*Note: VCC Min. is 4.75 volts, VCC is nominally 5.0 volts.  All voltages values are DC.