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4.4 Remote
Interfaces
This section provides operational instructions for the three remote interfaces for the
Lake Shore F71/F41 teslameter. Each of the three interfaces provided with the
teslameter source permit remote operation.
4.4.1 USB
The USB interface provides a convenient way to connect to most modern
computers. The USB interface is implemented as a virtual serial com port connection.
This implementation provides a simple migration path for modifying existing
RS-232 based remote interface software. It also provides a simpler means of commu-
nicating than a standard USB implementation
.
4.4.1.1 Physical Connection
The teslameter has a B-type USB connector on the rear panel. This is the standard
connector used on USB peripheral devices, and it allows the common USB A-type to
B-type cable to be used to connect the teslameter to a host PC. The pin assignments
for A-type and B-type connectors are shown in section 6.7. The maximum length of a
USB cable, as defined by the USB 2.0 standard, is 5 m (16.4 ft). This length can be
extended using USB hubs every 5 m (16.4 ft) up to five times, for a maximum total
length of 30 m (98.4 ft).
4.4.1.2 Hardware Support
The USB interface emulates an RS-232 serial port at a fixed 115,200 baud rate, but
with the physical connections of a USB. This programming interface requires a cer-
tain configuration to communicate properly with the teslameter. The proper configu-
ration parameters are listed in the table below.
The USB hardware connection uses the full speed (12,000,000 bit/s) profile of the
USB 2.0 standard; however, since the interface uses a virtual serial com port at a fixed
data rate, the data throughput is still limited to a baud rate of 115,200 bit/s.
Baud rate
115,200
Data bits
8
Parity
None
Stop bits
1
Flow control
RTS/CTS
TABLE 4-4
Host com port
configuration
