## Vintage 1977 Telecommunications Modem / Serial Interface Circuit BoardUp for sale is a fascinating piece of early internet and network history: a vintage telecommunications modem interface card. Featuring classic mid-1970s single-sided trace layout engineering, this board was designed to handle serial communications or direct line signal modulation.### Key Details & Features:
* **Core Silicon:** Features a prominent vintage Motorola MC6850P Asynchronous Communications Interface Adapter (ACIA) chip with a 1976 date code (7640).
* **Clock Components:** Includes a premium silver Bliley BH6W 998.0 kHz crystal oscillator stamped with a 1977 date code (7702).
* **Modem Telemetry:** The bottom interface rail is fully equipped with a row of red telemetry status LEDs with explicit PCB silkscreen markings for ORIG (Originate), RX (Receive), TX (Transmit), and CAR (Carrier Detect).
* **Physical Condition:** Physically complete, un-stripped, and very clean for its age. All specialized silver canister capacitors, yellow WMF film caps, and discrete transistors remain structurally intact. The gold edge connector fingers at the top show minimal wear.### Condition Note:
This vintage networking circuit board is sold AS IS!!