Telpar SP-328 Data Logger Thermal Printer
Rev A 8-26-2010
Page 9 of 19
Section 4. INTERFACE SPECIFICATIONS
4.1 Serial Interface Specifications
The SP-328 can be used as either a serial or parallel device without requiring
any
switch or
jumper
settings. The SP-328
will automatically detect the interface which is sending data and
produce the appropriate printout. The serial Interface parameters are factory set internal to the
printer firmware. Serial interface parameters must be specified prior to shipment. The standard
factory setting for the RS-232 serial interface is
9600
Baud, No Parity,
8
Data Bits, 1 Stop Bits.
RS-232 Terminal Connector Serial Interface:
Pin
Signal
Description
1
TXD
Data Output from the printer to the host.
2
RXD
Data Input to the printer.
3
GROUND
Signal ground
4
BUSY
-10V when printer is unable to receive data.
There are two conventions used in the RS-232C interface; these are Data Terminal Equipment
(DTE) and Data Communications Equipment (DCE). Examples of DCE are modems,
multiplexers, and telephone data line interfaces. All other equipment which originates or
receives data such as terminals (including the SP-328) or computers is DTE. If two pieces of
DTE are to be interconnected it is necessary to transpose TXD and RXD as well as DTR and
CTS in the cable. This type of cable is called a null modem cable and must be used
if
the SP-
328 is to be connected to a host computer's serial port.
