Opcom 31451 D.I.A.L. Modem Board PC 01701-01 RJ-11 4-Channel Telecom Card

Opcom 31451 D.I.A.L. Modem Board PC 01701-01 RJ-11 4-Channel Telecom Card

The Opcom 31451 is a modem board designed for use in the Opcom D.I.A.L. (Direct Inward Access Line) telephone and communications system. This card handles analog modem communications within the Opcom system chassis, providing RJ-11 telephone interface connectivity for the D.I.A.L. platform. The board carries a 4-channel designation (CHAN4) and is fitted with a pair of RJ-11 jacks for line connections along with isolation transformers and relay switching components.

Specifications & What's Included

• Manufacturer: Opcom
• Model: 31451
• Part Number: PC 01701-01
• Type: D.I.A.L. Modem Board / Telecom Card
• Form Factor: PCB card / plug-in module
• Channel designation: CHAN4 (4-channel board)
• Ports: 2 x RJ-11 telephone jacks
• Edge connector: Gold-finger connector (P1), for backplane/system chassis installation
• Main controller IC: National Semiconductor ADC0809CCN (8-bit A/D converter, date code 8742)
• Logic ICs visible: COM4036E, RCA4029E, and multiple CMOS/TTL logic packages
• Relay modules: 2 x Aromat S5A1 (rated 0.1A 125VAC / 0.4A 24VDC per label)
• Isolation transformers: Elec-Trol branded line transformers (MEXCO 4747 series)
• Board copyright: © Opcom 2-6-86 PC 01701-01 (date code indicates 1986 design)
• Includes: Board only — no cables or accessories

Applications

The Opcom D.I.A.L. system was a business telephone and communications platform used in enterprise and institutional environments during the 1980s and 1990s. The 31451 modem board provided the analog telephone interface within the D.I.A.L. system chassis, enabling the system to communicate over standard telephone lines. This type of card is primarily sought by technicians and facilities maintaining legacy Opcom D.I.A.L. installations, or by engineers requiring the board for system repair, component harvesting, or reverse-engineering purposes.