Elo Touch Solutions

AccuTouch 2218 Combo (Dual Serial/USB) Controller

The 2218 controller is RoHS Compliant, part # E329179.

2218 Controller for AccuTouch TouchscreensSupply Voltage and Current

  • +5 VDC, nominal (+4.50 VDC to +5.25 VDC). Self powered only.
  • 25 mA standby minimum, typical at +5 VDC; during touch 110 mA typical
  • Average power dissipation is 0.56 W, typical


  • EIA 232E (Serial RS-232), DCE configuration. 8 Data Bits, 1 Stop Bit, No Parity, Full Duplex
  • Hardware handshaking: RTS/CTS
  • DSR is pulled HIGH (>+3V) by the 2218 when connected and powered.  DTR can be asserted by the host to interrupt the flow of data from the controller. 
  • Note that if the application does not monitor CTS, then an interval of approximately 5 seconds should be inserted between the issuance of a reset command and any other command.

Communication Parameters

  • Baud Rate 9600 (default), and 19200
  • 8 Data bits, 1 stop bit, no parity only


  • The 2218 is a full-speed USB device. If the USB is connected to the controller, the controller will communicate over the USB, and will not communicate over the serial port.
  • The 2218 is never powered from the USB – it is self-powered only.

Operating Modes

  • Full AccuTouch SmartSet protocol. Emulation of E281A-4002 protocol can be selected by SmartSet command.
  • Initial/ Stream/ Untouch/ Z-axis Enable Modes

Touch Resolution

  • 4096x4096, size independent

Conversion Time

  • Approximately 5.5 ms per coordinate set


Calculated MTBF is shown below:

MTBF Method and Temperature Calculated MTBF
In the first year
Telcordia SR-332, 25°C 1,038,435
Telcordia SR-332, 50°C 659,520
After the first year
Telcordia SR-332, 25°C 2,464,143
Telcordia SR-332, 50°C 853,910


  • Operating: 0°C to 65°C
  • Storage: -40°C to 85°C


  • Operating: 10% to 90% RH, noncondensing
  • Storage: 10% to 90% RH, noncondensing

Operating Altitude

  • 10,000 feet

Shock and Vibration

  • Three axis sine wave, 50Hz to 2kHz, 1G, 2 minutes/Octave with dwell on resonances


  • Per EN 6100-4-2 1995: Level 4. Contact discharge 8kV, air discharge 15kV.


  • The printed circuit board substrate is rated 94V0. All plastic components, such as headers and connectors, are also rated 94V0.


  • Four-layer surface-mount design with internal ground plane for EMI suppression


  • Total width: 1.38 inches (35.00 mm)
  • Total length: 2.36 inches (60.00 mm)
  • Total height: 0.45 inches (11.30 mm)
  • The mounting holes are plated through for chassis ground connection. Refer to the dimensional drawing under the Drawings tab.

The power/interface connector, P1, is a 1.25mm pitch 20 pin, top contact style connector, intended to be used with single wired pins in a 20 pin header. The pins are numbered as shown in Table 1. Matching header is MOLEX 51127-2005 housing or CS JS-2255-20-D1P, with MOLEX 50516-8041 terminals.

Table 1. Power/Interface Connector P1 Pin Numbers and Signal Names

P1 Pin Signal Name Signal Function P1 Pin Signal Name Signal Function
1 USB VCC +5V Power 2 GND Ground
3 D- USB D- 4 D+ USB D+
5 +5 V +5V Power 6 GND Ground
7 SDA 12C SDA 8 NC No Connection
9 LED LED Touch and System Health Status 10 NRST Reset signal
11 HDCD Serial Port 12 HDSR Serial Port
13 HRxD Serial Port 14 HRTS Serial Port
15 HTxD Serial Port 16 HCTS Serial Port
17 HDTR Serial Port 18 SCL Serial Port
19 GRN No Connection 20 NC do not use

Table 2. Serial Interface on Connector P1, Pins and Signal Names

Signal Name DB-9 Pin P1 Pin Sourced by Signal Function
DCD 1 11 ctlr "carrier detect", handshake = '0' (POSITIVE) when controller power on
DSR 6 12 ctlr "data set ready", handshake = '0' (POSITIVE) when controller power on
NRxD 2 13 ctlr serial data from controller to host
RTS 7 14 host "request to send", handshake = '0' (POSITIVE) when controller may send
NTxD 3 15 host serial data from host to controller
CTS 8 16 ctlr used as "ready to receive", handshake = '0' (POSITIVE) when host may send
DTR 4 17 host "data terminal ready", handshake = '0' (POSITIVE) when controller may send
RI 9 - n/u not used
SG 5 19 com signal ground

Signal electrical characteristics are given in Table 3. These specifications are extracted from references 2 and 3, and they comply to ANSI/EIA/TIA 232-F.

Table 3. Serial Signal and LED Electrical Characteristics

Parameter Value Signals EIA-232 Subsec.
Minimum ON state input volts 1 +3 volts NTxD, RTS, DTR 2.1.3
Minimum OFF state input volts 1 -3 volts NTxD, RTS, DTR 2.1.3
DC Load Resistance 5 kΩ ± 2 kΩ NTxD, DTR, RTS 2.1.4
Source Impedance (Power Off) > 300 Ω DSR, DCD,CTS, NRxD 2.1.5
Power-off condition interpretation ON condition RTS, DTR 2.1.5 
Output Voltage, Open Circuit 25 volts, max. 2 NRxD, DSR, DCD, CTS 2.1.6
Output Voltage into test load 3 >5, <15 volts 2 NRxD, CTS, DSR, DCD 2.1.6
Short Circuit Current <100 mA NRxD, DSR, DCD, CTS 2.1.6
Transition Characteristics per EIA-232-E 4 NRxD, DSR, DCD, CTS 2.1.7
External LED short circuit current 0.5mA nominal LED N/A

1 Measured with respect to circuit AB, Signal Ground.
2 Absolute magnitude.
3 Output voltage measured over the entire range of test load from 3000 ohms to 7000 ohms.
4 The transition characteristics comply with ANSI EIA/TIA-232-E while the controller is powered on; during power up and power down some of the criteria will not be met.

The AccuTouch touchscreen connector, P2, is a single row by five-position header with 0.025 inch square pins spaced on 0.100 centers. Connector P2 is a Molex 22-05-3051 and mates with the receptacle on the AccuTouch touchscreen cable. The pins are numbered as shown in Figure 1. The withdrawal force exceeds 2 lbs.

3000U USB Controller

Figure 1. P2, AccuTouch Touchscreen Cable-Board Mounted Header and Cable-Mounted Plug

Table 4. Touchscreen Connector, P2, Pins and Signal Names

P2 Pin Signal Name Signal Description
1 H Drive signal attached to the touchscreen substrate upper right corner when viewed from a user's perspective
2 X Drive signal attached to the substrate lower right corner
3 S "Sense" signal attached to the touchscreen coversheet
4 Y Drive signal attached to the substrate upper left corner
5 L Drive signal attached to the substrate lower left corner

The 2218 has no jumpers.

A green LED indicates controller status as below:

LED Blink Rate  Function
Once per second Normal condition, untouched state
On continuously Touched state
Twice per second Error detected
  • Elo controllers are "CNR/USR" UL Recognized Components for USA and Canada, Category NWGQ2, Information Technology Equipment Including Business Equipment.
  • Elo controllers are TÜV Bauart certified as components.
  • Elo controllers have been tested for compliance with FCC Part 15 Class B limits.
  • Depending on the application, it may be necessary to pay special attention to system grounding and shielding, and it may be necessary to apply ferrite suppressor beads.
  • Agency approval certificates for all Elo controllers and touchscreens (366K PDF)
  • Look up product statement of compliance by part number
  • Serial cable: P/N D16890-000
  • USB cable: P/N D38640-000
  • Dual serial/USB cable: P/N D40022-000