Bell-202/202T Modems

These modems have been designed with many commonly requested features including 900Hz soft-carrier turnoff, LED indicators, digital control over most timing parameters (in 1 millisecond increments), transmit levels from 0 to -31db, a PTT (Push to Talk) circuit, and input power from 5 to 160 VDC. The primary modem circuitry is based on commercially available ICs with many years of field proven operation.

All Bell modems are available in a 19″ rack configuration with a 16-slot custom backplane, or packaged in a metal box. For IED/RTU manufacturers, a low-cost “board only” version can mount directly in the Remote unit. Power, Timing, Levels, Isolation, LEDs, Other, Packaging, Testing your modem, Modem Part Numbers

RACK MOUNT MODEM FEATURES The rack mount chassis measures 19 inches wide by 5.25 (3U) inches high, and fits into standard EIA cabinets. The chassis holds 16 single-channel modems and redundant power supplies.

The modems are hot swappable. The 16 Channel Modem Chassis contains slots for two standard 3U VME power supplies. The power supply has a 40-watt universal input (90 to 254VAC) with overvoltage protectionand continuous short circuit protection. The power supply output is +5VDC at 8.0 amps and does not require a minimum load to obtain regulation. The power supply module contains a +5VDC adjustment pot accessible from the front panel for adjustment +/- 0.3 volts. The 16 Channel modem chassis can run on a single supply. The second power supply can be added to provide the user with a higher mean time between failure. Power supplies are also hot swappable.

STANDALONE BELL 202/202T AND V.23 MODEM FEATURES The standalone modems are available in two formats: in a metal enclosure (Box) or with 3U VME faceplate. The metal enclosure is 187 x 105 x 36 mm or 7.35” x 4.14” x 1.42”. Flanges are provided at both ends for mounting the equipment. The 3U VME mounting bracket has screw downs for standard VME chassis.

BELL 202/V.23 MODEMS – STANDALONE

MODEL                    MOUNTING OPTIONS                                                          INPUT POWER

DM-FSK-I-B            No enclosure, board only                                                 Regulated 5 VDC or unregulated

DM-FSK-I-V            VME Mounting bracket for mounting                            12-160 VDC

                                   in a 3U  logic chassis without backplane.               

                                   Requires access to rear of board for

                                   external power, RS-232 and Telco connections

DM-FSK-I-M           Metal box enclosure

BELL 202/V.23 MODEMS – RACK MOUNT

MODEL                    MOUNTING OPTIONS                                                          INPUT POWER

DM-FSK-X-V           Single channel modem for use with                             From SM-RACK-16 chassis backplane

                                   SM- RACK-16 chassis and backplane

SM-RACK-16          19” VME Rack mount chassis with 5V logic                 120 VAC                  

                                   power supply holds 16 DM-FSK-X-V modems

SM-RACK-PS          Redundant 5V logic power supply                                 120 VAC