IG202T/V23 Industrial Grade Bell 202 & V23 1200 Baud Modem


IG202T/V23 Industrial Grade Modem is the most dependable and easy to install Bell 202 & V23 compatible leased line modem available today!!!





The Data Connect low speed IG-202T/V23 modem is designed and manufactured for rugged industrial communication networks. It is the most industrial grade 202T & V23 modem on the market operating from -40C to 85C (185F). The IG-202T/V23 modem delivers cost effective and reliable 1200bps asynchronous solutions for point to point and multipoint connectivity. For optimum performance, the modem employs FSK modulations to be compatible with Bell-202T and ITU-V23 standards and communicates over a variety of transmission lines.

The IG-202T/V23 modem is ideal for industrial communication applications including SCADA systems, RTUs, traffic monitor and control, and industrial and automation networks. The

IG-202T/V23 modem supports RTUs with switch selectable settings and no software code commands. The IG-202T/V23 modem is designed to operate 4-wire full duplex or 2-wire half duplex over, Special Access Service VG6 that is a 4-wire channel suitable for the access segment of most voice grade data circuits, unconditioned leased lines, or private metallic circuits.

The IG-202T/V23 modem can operate over a wide range of AC or DC power supply voltages and temperatures. With proven reliability and ease of installation the IG-202T/V23 is ideal for point-to-point and point-to-multipoint polling networks, where reliability and low-network latency are critical for system performance. The IG-202T/V23 modem has internally Flow Control options of “Constant On” and “Controlled by RTS”. The Flow Control options are Dip-Switch selectable and the options performs the same functionality as DataSense or other flow control and buffering schemes. With its Auto-RTS mode, the modem can support DTE/RTUs with 3-wire serial interface (TD, RD, SG) in point-to-point and multi- point polling applications.


The IG202T/V23 industrial grade Bell 202/V23 modem has selectable EIA RS-232/V.24 and RS-485 DTE support. It also features built-in diagnostics for local and remote testing. The configuration and options on the IG202T/V23 is provided by DIP switches and jumpers,

eliminating the need for an AT command set. Unlike any other 202T/V23 modem you can buy, the IG202T/V23 has heavy-duty surge protection at the power supply and leased line inputs. IG202T/V23 also uses an isolated DC to DC power converter for protecting critical DC or battery power systems.



General Specifications

Data rate: 0-1200 bps

Data format: Transparent to DTE

DTE interface: EIA RS-232/V.24, or RS-485 compatible

Line conditions: TELCO voice band 4- or 2-wire leased line, conditioned or unconditioned lines. Private metallic circuits

Operating modes: 2-wire half-duplex or 4-wire full-duplex

Modulation: FSK, Bell 202T or V.23 compatible

  • Mark = 1200 Hz, Bell 202 & 1300 Hz, V.23
  • Space = 2200 Hz, Bell & 2100 Hz, V.23
  • Soft Carrier = 900 Hz Bell 202T only)

RTS-CTS Delay: 10 or 33 ms, Bell 202T & 33 ms, V.23

Receiver dynamic range: 0 to –43 dBm

Operating temperature: -40°C to +85°C

Power supply: Wide range switching power supply:

  • IG202T/V23 (AC version): 90 to 265 Volts AC, 50/60 Hz, single phase or 90 to 400 VDC
  • IG202T/V23-DC (DC version):10 to 60 Volts DC

Surge protection: Leased line, up to 15KV

Flow control: Constant or RTU Controlled, DIP switch selectable

Carrier loss recovery: Automatically

Auto RTS: Support DTE without hardware RTS

Anti-streaming: 30-second timer to prevent transmitter lock-up network

Mechanical Specifications

Enclosure: ABS with removable top cover Dimensions: 4.1” wide x 4.9” long x 1.40” high

Weight: 0.5 lbs without AC to DC power converter module

Interface connectors

Leased Line: 4-position RJ-11C modular Jack

Data Terminal Equipment: DB-9 female connector (for RS-232) RJ-11C module jack (for RS-485)


Interface Connector Pin Assignments


Leassed Line RJ11C Pin Assignments
Pin # Signal
1 Not Used
2 TX
3 TX (TX/RX)
4 TX (TX/RX)
5 RX
6 Not Used


Back-to-Back Connection to a Second Modem









RS-232 (DTE) Interface

Signal Name Modem Input/Output DB9 Pin Description
DCD OUTPUT 1 Data Carrier Detected
RXD OUTPUT 2 Receive Data
TXD INPUT 3 Transmit Data
SG 5 Signal Ground
DSR OUTPUT 6 Data Carrier Detected
RTS INPUT 7 Request To Send
CTS OUTPUT 8 Clear To Send


RS-485 (DTE) Interface
RJ11 Pin Number Corresponds to Sgnal Name Modem Inpt or Output
1 Not Used NA
2 RxD+ Output
3 RxD- Output
4 TxD+ Input
5 TxD- Input
6 Not Used NA


Environmental Specifications

Operating temperature: -40 to + 85 Degrees Celsius Storage temperature: –40 to +125 Degrees Celsius Operating humidity: 5 to 95 %, non-condensing Line isolation: 3750 V RMS

Surge protection: Leased line up to 15K VA



Product in Test


Data Rate

 Cable Equalizer select Option Operating over TELCOLeased Lines  

Operating Distance

w/ 26 AWG cable


Operating Distance

w/ 24 AWG cable




1200 bps





100,000 FT

(18.94 miles)

125,000 FT

(23.67 miles)


1200 bps





140,000 FT

(26.52 miles)

175,000 FT

(33.14 miles)




300 bps





130,000 FT

(24.62 miles)

162,000 FT

(30.68 miles)


300 bps





182,000 FT

(34.47 miles)

227,000 FT

(42.99 miles)


Test conditions:       1)    Point-to-point, full duplex, switched carrier is used.

  • Test message is the FOX message
  • Polling error to be less than 1 in 1000


Modem Switch Settings
ON OFF (Default)
DIP Switch S1
SW1-1:  Auto RTS Enable Disable

SW1-2:  RTS-CTS Delay (Bell 202 mode only)



10.0 ms (Bell 202T) 33 ms (V.23 mode)
SW1-3:  Flow Control Constant ON Controlled by RTS
SW1-4:  Soft Carrier (Bell 202 mode only) Enable Disable
SW1-5: Anti-streaming Enable (30 Seconds) Disable
SW1-6:  2- or 4-wire leased line 2-wire half duplex 4-wire full duplex
SW1-7:  Transmitter Termination Controlled by RTS 600 ohms
SW1-8:  Receiver Termination 600 ohms High (approx 20K)


S-232 or RS485 Select


RS-232/ V.24 Interface



RS485/RS422 Interface


JP2: Pin 1 to Pin3 Pin 2 to Pin 4


JP2: Pin 3 to Pin 5 Pin 4 to Pin 6


Transmit Levels

Transmit Level JP1 Jumper Settings
0 dBm Pin 1 to Pin 2
−4 dBm Pin 3 to Pin 4
−8 dBm Pin 5 to Pin 6
−12 dBm Pin 7 to Pin 8




OLNEY, MD 20832


O: 301.924.7400 EXT. 17

F: 301.924.7403