Toshiba TRST-A10 SERIES Technical specifications

PRINTED IN JAPAN
TOSHIBA REMOTE RECEIPT PRINTER
TRST-A10 SERIES
Document No. EO10-13009A
Original Nov., 2007
(Revised Feb., 2008)
Product Descri
p
tion

EO10-13009A
TABLE OF CONTENTS
Page
1. OUTLINE -------------------------------------------------------------------------------------------------1- 1
1.1 FEATURES OF THE PRINTER -----------------------------------------------------------------------1- 1
1.2 DESCRIPTION OF MODEL NUMBER --------------------------------------------------------------1- 2
1.3 OVERVIEW AND DIMENSIONS ----------------------------------------------------------------------1- 3
1.3.1 Front View/Rear View --------------------------------------------------------------------------------1- 3
1.3.2 Connectors ----------------------------------------------------------------------------------------------1- 3
1.3.3 LED and Feed Button ---------------------------------------------------------------------------------1- 4
1.3.4 Datascope Mode ---------------------------------------------------------------------------------------1- 6
1.4 SYSTEM CONFIGURATION ---------------------------------------------------------------------------1- 7
1.5 BASIC SPECIFICATION --------------------------------------------------------------------------------1- 8
1.6 ELECTRONIC SPECIFICATIONS --------------------------------------------------------------------1- 9
1.7 DRAWER INTERFACE ---------------------------------------------------------------------------------1-21
1.7.1 Drawer Kick Drive Signal ---------------------------------------------------------------------------1-21
1.7.2 Electronic Characteristics ---------------------------------------------------------------------------1-21
1.7.3 Connector Description -------------------------------------------------------------------------------1-21
1.7.4 Drive Circuit --------------------------------------------------------------------------------------------1-22
1.8 DC POWER CONNECTOR ----------------------------------------------------------------------------------1-23
1.9 POSITION OF CUTTER --------------------------------------------------------------------------------------1-23
1.10 SENSORS --------------------------------------------------------------------------------------------------------1-24
2. SUPPLY SPECIFICATIONS ------------------------------------------------------------------------2- 1
2.1 EFFECTIVE PRINTING AREA ------------------------------------------------------------------------2- 1
2.2 DESIGN OF PAPER ROLL -----------------------------------------------------------------------------2- 3
CAUTION!
1. This manual may not be copied in whole or in part without prior written permission of TOSHIBA
TEC.
2. The contents of this manual may be changed without notification.
3. Please refer to your local Authorised Service representative with regard to any queries you
may have in this manual.
Copyright © 2007
by TOSHIBA TEC CORPORATION
All Rights Reserved
570 Ohito, Izunokuni-shi, Shizuoka-ken, JAPAN

1. OUTLINE EO10-13009A
1.1 FEATURES OF THE PRINTER
1-1
1. OUTLINE
1.1 FEATURES OF THE PRINTER
1) This printer is a single station printer for 80 mm width receipt and is equipped with the RS-232C
serial interface, USB interface or parallel interface (option), conforming to the ESC/POS
commands.
2) Paper drop-in mechanism realizes easy paper loading and head cleaning. When setting or
replacing the paper roll, only load it into the printer and close the cover.
3) This printer performs in thermal direct method at high speed (max. 225 mm/s) with less noise.
4) Since the paper outlet is provided at front side of the printer, the receipt can be taken out easily
and flexible installation is possible.
5) The cover closed tightly prevents any foreign material and liquid from getting into the printer.
6) This printer performs barcode printing with special commands.
7) Print layout can be variously arranged.
8) User-defined characters and logos can be stored into the flash memory.
9) An automatic cutter is provided as standard. (Partial cut)
10) The body color is selectable from Fair White (FW) and Cool Black (CB) as standard to color
coordinate with the POS terminal to be connected.
11) The AC adapter can be used in every country.
NOTE: Every size is written in millimeter (mm) in this manual. To obtain the size in inch, divide by 25.4.

1. OUTLINE EO10-13009A
(Revision Date: Feb. 06, 2008)
1.2 DESCRIPTION OF MODEL NUMBER
1-2
1.2 DESCRIPTION OF MODEL NUMBER
Model name description
TRST-A1 - - -
NOTE: Some combinations of the above specifications are not developed as products. For
details, please refer to your nearest authorized TOSHIBA TEC representative.
0
Destination Code
QM: Standard for Worldwide
CN: China
RoHS compliance
R: RoHS-Compliant model
Body Color
F: Fair White
C: Cool Black
AC Adaptor & Power Cable
Blank : Without AC adapter and power cable
1 : With AC adapter, without power cable
Interface Type
S: Standard Interface (Serial & USB)
P: Parallel Interface
Printer Type
5: Dual Side Printer
0: Single Side Printer

1. OUTLINE EO10-13009A
1.3 OVERVIEW AND DIMENSIONS
1-3
1.3 OVERVIEW AND DIMENSIONS
1.3.1 Front View/Rear View
1.3.2 Connectors
1 [DC24V] (Socket connector)
The built-in AC adapter supplies +24V power to the printer through this connector. Do not
connect anything other than the Toshiba TEC Specified AC adapter.
2 [Serial interface connector]
An interface cable which connects the printer to a POS terminal or Personal Computer is
connected to this connector. A RS-232C interface cable (Serial I/F model)
Front View Rear View
Feed Button
LED Printer Cover
Cover Top
Power Switch
4 1 23
5 1

1. OUTLINE EO10-13009A
1.3 OVERVIEW AND DIMENSIONS
1-4
3 [USB interface connector]
An interface cable which connects the printer to a POS terminal or Personal Computer is
connected to this connector, a USB I/F (V2.0 Full Speed) is needed for this connector.
4 [Drawer interface Connector] [CDKO] (6 pin modular connector)
A drawer cable which connects the printer to a drawer is connected to this connector. To this
connector, a Toshiba drawer can be connected. Do not connect anything other than the
connectable drawer.
5 [Parallel interface connector]
An interface cable which connects the printer to a POS terminal or Personal Computer is
connected to this connector. A Parallel interface cable (Parallel I/F model) is needed for this
connector.
1.3.3 LED and Feed Button
POWER LED (Green)
Lights when the power is turned on.
ERROR LED (Blinking Green)
The Error LED indicates an error by
blinking.
FEED Button
Used to feed receipt paper. A touch
of this button causes one line feed.
Pressing and holding it feeds the
paper continuously. When the power
switch is turned on while the [FEED]
button is pressed and held, the
printer will perform a self test print.

1. OUTLINE EO10-13009A
1.3 OVERVIEW AND DIMENSIONS
1-5
Error Status Table
Green LED Blinking (Slow)
Problem What to Do Where to Go
Receipt paper is low* There are about 4 ½ meters, ±3 meters, (15 feet,
±10 feet) of paper left. Change the paper soon to
avoid running out of paper part way through a
transaction.
Green LED Blinking (Fast)
Problem What to Do Where to Go
Receipt paper is out Change the paper now. Do not run a transaction
without paper as the data may be lost.
Receipt cover is open Close the cover. The printer will not operate with
the cover open.
Knife failure Open the receipt cover and check the knife. Clear
any jammed paper you can see. Tear off any
excess paper against the tear-off blade.
NOTE:If other LED status except for the above occurs, turn the power off, and then on. If this does
not restore the LEDs, contact your nearest TOSHIBA TEC representative for assistance.

1. OUTLINE EO10-13009A
1.3 OVERVIEW AND DIMENSIONS
1-6
1.3.4 Datascope Mode
Datascope Mode allows the user to test the printer’s communications. When in Datascope Mode
the printer receives all communications, but instead of executing the commands it prints them
out on receipt paper as hexadecimal numbers in the order received. For example, the ASCII
character “A” is printed as the hexadecimal number 41 an so on.
To run the Datascope Mode:
After you have enabled the Data scope Mode through the Configuration Menu, exit the
Configuration Menu.
1. Run a transaction from the host computer.
All commands and data sent from the host computer will be printed as hexadecimal numbers as
shown in the illustration.
30 31 32 33 34 35 36 37 38 39 40 41 : 0 1 2 3 4 5 6 7 8 9 @ A
41 42 43 44 45 46 47 48 49 50 51 52 : A B C D E F G H I J K L
To exit the Datascope Mode:
1. Enter the Configuration Menu again
2. Disable the Data scope Mode
3. Exit the Configuration Menu
The printer is in Normal Mode and can communicate with the host computer.

1. OUTLINE EO10-13009A
1.4 SYSTEM CONFIGURATION
1-7
1.4 SYSTEM CONFIGURATION
Serial or Parallel
Interface
Drawer Interface
(Drawer Kick Specification)
DC 24V
TOSHIBA TEC DRAWER
(DRWST-51A-8MVG-QM-R,etc.)
POS Terminal
(ST-A10 series, etc.)
AC Adapter

1. OUTLINE EO10-13009A
(Revision Date: Feb. 06, 2008)
1.5 BASIC SPECIFICATIONS
1-8
1.5 BASIC SPECIFICATIONS
Item Description
Printing method Line thermal dot printing method
Printing width (Font Size 1)
80 mm (576 dots)
58 mm (432 dots)
(Font Size 2)
80 mm (560 dots)
58 mm (424 dots)
Resolution 203.2 dpi x 203.2dpi
Printing speed Max. 9 ips max (225 mm/sec) for 75W, 55W mode
2 color printing Max 50 mm/sec
(Font Size 1)
80 mm Paper
48 Column (at 16.9 cpi Standard Character)
64 Column (at 22.6 cpi Compress Character)
24 Column (Double bytes Font)
58 mm Paper
36 Column (at 16.9 cpi Standard Character)
48 Column (at 22.6 cpi Compress Character)
16 Column (Double bytes Font)
Printing columns
(Font Size 2)
80 mm Paper
42 Column (at 15.6 cpi Standard Character)
56 Column (at 20.3 cpi Compress Character)
58 mm Paper
32 Column (at 15.6 cpi Standard Character)
42 Column (at 20.3 cpi Compress Character)
Character size Font A: 1.5 x 3.00 mm
Font B: 1.125 x 3.00 mm
Character types Code pages PC437, PC850, PC852, PC857, PC858, PC860,
PC863, PC865, PC866 PC949(STD Model only),
PC54936(China model only) and PC1252
Logo registration and print User defined characters and logos are downloadable in the
flash
memory.
Line spacing 7.52 (default) and variable lines per inch.
Printable bar codes UPC-A, UPC-E, JAN13 (EAN), JAN8 (EAN), Code 39, Code
128, Interleaf 2 of 5, Codabar, PDF417, Code 93
Cut method Partial Cut
Paper Thermal paper roll: 80 mm x dia. 83 mm (Max)
Thermal paper roll: 58 mm x dia. 83 mm (Max)
Interface RS232C I/F or USB I/F (V2.0 Full Speed). Parallel as Option.
Input buffer 4K bytes/128 bytes
Printer supply input voltage Rated output: DC 24V, 3.15A (75W)
Power consumption 3.15A (75W Power Supply), 2.29A (55W Power Supply)
AC adapter specification Rated input: AC 100 – 240V, 50/60Hz, 2.0A max
Rated output: DC 24V, 3.15A (75W)
Body color Fair White (FW) or Cool Black (CB)
Operating temperature 5ºC to 50ºC
Operating humidity 10% to 90% RH (no condensation)
Storage temperature -20ºC to 60ºC
Storage humidity 10% to 90% RH (no condensation)
Weight 1.7 Kg
Dimension 145.5 mm (W) x 185.5 mm (D) x 141.0 mm (H)

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-9
1.6 ELECTRONIC SPECIFICATIONS
1.6.1 CPU ............................... UP0703111A
1.6.2 Serial Interface (RS232)
1. Specification
(1) Synchronization method: Asynchronous
(2) Baud rate: 9600, 19200, 38400,57600,115200 BPS (selectable)
(3) Transmission parameter:
Start bit: 1 bit
Word length: 7 bit or 8 bit (selectable)
Parity: None, even, odd (selectable)
Stop bit: 1,2 bits selectable
(4) Signal level:
Transmitter:
MARK = “1” (-5V~-15V)
SPACE = “0” (+5V~+15V)
Receiver:
MARK = “1” (-3V~-25V)
SPACE = “0” (+3V~+25V)
(5) Receive data (RD signal):
MARK = 1
SPACE = 0
(6) Receive control (DTR signal):
MARK: Data transmission is impossible.
SPACE: Data transmission is possible.
(7) Send control (TD signal):
DC1 code (17H) X-ON: Data can be received.
DC3 code (19H) X-OFF: Data cannot be received.
2. Connector description
No. Signal I/O Description
1 DCD (NC) Data Carrier Detect (Not connected )
2 RX Input Receive data
3 TX Output Sending Data
4 DTR Input Data Terminal Ready
5 SG Send to Ground
6 DSR Input Data set ready
7 RTS Output Printer BUSY signal
8 CTS Input Clear to send
9 RI (NC) Ring Indicator (Not connected )

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-10
RS232 9 Pin to 9 Pin Cable
9 Pin Female 9 Pin Female
1 DCD DCD 1
2RxD RxD 2
3TxD TxD 3
4DTR DTR 4
5 LGND LGND 5
6DSR DSR 6
7RTS RTS 7
8CTS CTS 8
9 SHLD SHLD 9
Applicable connector: D-sub connector
Printer side: 1002-09MS4G-L (CHUFON or equivalent)
Cable side: DB9 RS232 F/F serial cable
NOTE: The RS-232C signal is according to EIA RS-232C.
3. I/O signal
(1) RX
This is a serial receive data signal. When a framing error, overrun error, or parity error occurs,
the data is printed as “?”.
(2) DTR, RTS
When these signals are in ready status, data and command can be written. If the data is
written in BUSY status, an overrun error occurs, causing the previous data to be ignored. Data
can also be written into input buffer during printing. When the power is turned on, when the
printer is in on-line mode during test print, or when the printer is reset, these signals are in
BUSY status.
(3) TX
This is used for sending data from printer.
In Xon/Xoff control, when the printer enters BUSY status, the printer outputs DC3(13H) signal.
When the printer enters READY status, the printer outputs DC1(11H) signal to the host.

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-11
(4) DSR
When the DTR/DSR control is selected, the printer confirms this signal is SPACE and then
sends the status data. When it is not selected, the data is sent without DSR.
(5) SG
Signal ground.
(6) CTS
Clear to send. This is asserted by host terminal to acknowledge RTS and allow printer to
transmit.
Pin 2 - Transmitted Data (TxD) This signal is active when data is transmitted from the DTE
(computer)
device to the DCE (printer)device. When no data is transmitted, the signal is held in the mark
condition
(logic '1', negative voltage).
NOTE: Pin 2 on the DCE device is commonly labeled "Received Data", although by the
EIA232 standard it should still be called Transmitted Data because the data is thought to be
destined for a remote DTE device.
Pin 3 - Received Data (RxD) This signal is active when the DTE device receives data from
the DCE device. When no data is transmitted, the signal is held in the mark condition (logic '1',
negative voltage).
NOTE: Pin 3 on the DCE device is commonly labeled "Transmitted Data", although by the
EIA232 standard it should still be called Received Data because the data is thought to arrive
from a remote DTE device.
Pin 4 - Request to Send (RTS) This signal is asserted (logic '0', positive voltage) to prepare
the DCE device for accepting transmitted data from the DTE device. Such preparation might
include enabling the receive circuits, or setting up the channel direction in half-duplex
applications. When the DCE is ready, it acknowledges by asserting Clear to Send.
NOTE: Pin 4 on the DCE device is commonly labeled "Clear to Send", although by the EIA232
standard it should still be called Request to Send because the request is thought to be
destined for a remote DTE device.
Pin 5 - Clear to Send (CTS) This signal is asserted (logic '0', positive voltage) by the DCE
device to inform the DTE device that transmission may begin. RTS and CTS are commonly
used as handshaking signals to moderate the flow of data into the DCE device.
NOTE: Pin 5 on the DCE device is commonly labeled "Request to Send", although by the
EIA232 standard it should still be called Clear to Send because the signal is thought
to originate from a remote DTE device.

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-12
4. Error detection
If a parity error, framing error, and overrun error is detected, the data is stored into the buffer
as “?
(1) Framing error: This error occurs when no stop bit is found in the frame. The data is
stored into the buffer as “?”.
(2) Parity error: When an error is detected at the parity check, the data is stored into the
buffer as “?”.
(3) Overrun error: When this error is detected, the data is stored into the buffer as “?”.
5. Receive control
In case DTR/DSR control is selected, the printer receives data from the host when a BUSY
signal is low level, however, the printer cannot receive it when the BUSY signal is high level.
In case DTR/DSR control is not selected, the printer receives data from the host after sending
XON signal, however, it cannot send data after sending XOFF
6. Buffering
DTR signal and TD signal are provided as a control signal for data transmission to input buffer.
(1) DTR signal
(2) TD signal

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-13
5Kohm
DTR (RxIN)
DSR, DCD (RxOUT)
5Kohm
TxD (RxIN)
RxD (RxOUT)
5Kohm
RTS
(
RxIN
)
CTS (RxOUT)
RxD (TxOUT)
TxD (TxIN)
DSR,DCD
(
TxOUT
)
DTR (TxIN)
CTS (TxOUT)
RTS (TxIN)
7. Electric specification
For RS232, SP3243E or equivalent
Input signal (RxD, DSR, CTS)
[ Printer side ] [ Host side ]
Where x denotes 1, 2 or 3
Output signal (DTR, TxD, RTS)
[ Printer side ] [ Host side ]

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-14
1.6.3 USB Interface
1. Specification
Version 2.0 full speed.
2. Connector description
Pin Signal Description
1 VCC +3.3Vdc
2 D-
Data – (Differential pinout)
3 D+
Data +(Differential pinout)
4 SG Signal Ground
3. I/O signal
USB is a serial bus. It uses 4 shielded wires: two for power (+3.3V & GND) and two for
differential data signals (labelled as D+ and D- in pinout). NRZI (Non Return to Zero Invert)
encoding scheme used to send data with a sync field to synchronise the host and receiver
clocks. In USB data cable Data+ and Data- signals are transmitted on a twisted pair. No
termination needed. Half-duplex differential signaling helps to combat the effects of
electromagnetic noise on longer lines. Contrary to popular belief, D+ and D- operate together;
they are not separate simplex connections.
4. Error detection
The core bit error rate of the USB medium is expected to be close to that of a backplane and
any glitches will very likely be transient in nature. To provide protection against such transients,
each packet includes error protection fields. When data integrity is required, such as with
lossless data devices, an error recovery procedure may be invoked in hardware or software.The
protocol includes separate CRCs for control and data fields of each packet. A failed CRC is
considered to indicate a corrupted packet. The CRC gives 100% coverage on single- and
double-bit errors.
5. Receive control
ML60851E supports three types of transfers: Control, Bulk and Interrupt Transfers as defined by
USB Specifications.
-Control Transfer is required for transfer of configuration, commands, and status information
between the host and devices.
-Bulk Transfer enables transfer of large amounts of data when the bus bandwidth is adequate.

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-15
-Interrupt Transfers are used when moderate amounts of data have to transfer within a
specific amount of time.
-The ML60851E requests interrupts to the local MCU, etc., by asserting the -INTR pin.
-Transfer of handshake packet in a direction opposite to that of the data packet.
When packet transfer is completed normally, an ACK packet is returned and the operation
proceeds to the next packet transfer.
The ML60851E requests the local MCU to transmit or receive a packet of data by asserting the
INTR pin. The interrupt cause will be “packet ready”. The transmit packet ready interrupt is one
that requests that The packet of data to be transmitted be written in the transmit FIFO, and the
receive packet ready
interrupt is one that requests the local MCU to read out the data that has been received and
stored in the receive FIFO. The above procedures of transferring one packet of data are
explained below for
transmission and reception separately.
1) During transmission
The local MCU writes one packet of data that has to be transmitted in the transmit FIFO of the
corresponding EP in the ML60851E, and sets the transmit packet ready bit of the corresponding
EP status register of the ML60851E. When the host transmits the IN token packet to the
ML60851E specifying the communication method, etc., the ML60851E transmits to the host the
data packet stored in the above transmit FIFO. When the host receives one data packet
normally, it returns the ACK packet to the ML60851E. Consequently, the ML60851E resets the
transmit packet ready status, thereby completing the transfer of one data packet over the USB
bus. When the transmit packet ready status is reset, the ML60851E gives a request to the local
MCU in terms of a transmit packet ready interrupt thereby prompting the local MCU to write the
next packet of data to be transmitted.
2) During reception
The host sends to the ML60851E an OUT token followed by a data packet. The ML60851E
stores the received data packet in the receive FIFO of the corresponding EP. When it is
confirmed that all the data packets have been accumulated and that there is no error, the
ML60851E returns an ACK packet to the host. At the same time, the receive packet ready bit of
the corresponding EP status register will also be set and a request is sent to the local MCU in
terms of an interrupt. Upon receiving this interrupt, the local MCU reads out the received data
from the ML60851E and resets the receive packet ready bit.
6. Buffering
When a read request is sent to USB, the USB host controller will continue to read 64 byte
packets until one of the following conditions is met:
1. It has read the requested size (default is 4 Kbytes).
2. It has received a packet shorter than 64 bytes from the chip
3. It has been cancelled
While the host controller is waiting for one of the above conditions to occur, NO data is received
by our driver and hence the user's application. The data, if there is any, is only finally transferred
after one of the above conditions has occurred.

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-16
Normally condition 3 will not occur so we will look at cases 1 and 2. If 64 byte packets are
continually sent back to the host, then it will continue to read the data to match the block size
requested before it sends the block back to the driver.
If a small amount of data is sent, or the data is sent slowly, then the latency timer will take over
and send a short packet back to the host which will terminate the read request.
7. Electric specification
For USB, ML60851 or equivalent
[Printer side] [Host side]
3.3V 3.3V
1.5Kohm
D-
D+
2.2ohm
2.2ohm
D-
D+

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-17
1.6.4 Parallel Interface
(i) Compatibility Mode (Host to Printer: Conforming to Centronics interface)
(1) Data input method: 8-bit parallel
(2) Synchronization method: nStrobe signal externally supplied
(3) Hand shake: nAck signal and Busy signal
(4) Signal level: All signals are TTL compatible.
(ii) Reverse Mode: (Printer to Host)
Status data is transmitted from the printer to the host in Nibble mode.
Description: Data transmission from the asynchronized printer that is controlled by the host
is considered. In Nibble mode, each of 4-bit data is transmitted to the host with the existing
control line.

1. OUTLINE EO10-13009A
1.6 ELECTRONIC SPECIFICATIONS
1-18
(iii) Connector Description
Pin Source Compatibility mode Nibble Mode
1 Host Nstrobe HostCLK
2 Host/Ptr Data0(LSB) Data0(LSB)
3 Host/Ptr Data1 Data1
4 Host/Ptr Data2 Data2
5 Host/Ptr Data3 Data3
6 Host/Ptr Data4 Data4
7 Host/Ptr Data5 Data5
8 Host/Ptr Data6 Data6
9 Host/Ptr Data7 Data7
10 Printer Nack PtrClk
11 Printer Busy PtrBusy/Data3.7
12 Printer Perror AckDataReq/Data2.6
13 Printer Select Xflag/Data1.5
14 Host nAutoFd HostBusy
15 NC NC
16 GND GND
17 FG FG
18 Printer Logic-H Logic-H
19 GND GND
20 GND GND
21 GND GND
22 GND GND
23 GND GND
24 GND GND
25 GND GND
26 GND GND
27 GND GND
28 GND GND
29 GND GND
30 GND GND
31 Host nInit NInit
32 Printer nFault nDataAvail/Data0.4
33 GND GWDND GWDNC
34 Printer NC NC
35 Printer NC NC
36 nSelectln 1284-Active
NC: None connect
ND: Not defined
Applicable connector: Printer side: 57RE-40360 (AMPHENOL type or equivalent)
Cable side: 57-30360 (AMPHENOL type or equivalent)
NOTE: The initial letter “n” of the signal indicates a “L” active signal. Bi-directional data
transmission is possible with all the above signals.
Be sure to use the twisted pair lines for each signal, and connect the return side to the
signal ground level.