Black Box RS-232 to 5V TTL Bidirectional Converter DB9

The Black Box IC1157A is a bidirectional converter that lets RS-232 equipment talk directly with devices that rely on 5 V TTL logic. It sits in line between the two interfaces and automatically shifts voltage levels in both directions on the transmit and receive lines. Because it pulls the small amount of power it needs from the RS-232 port, you do not have to hunt for an extra supply or add a wall wart, which keeps installations tidy.

With support for serial rates up to 115 kbps, the converter carries typical control signals for sensors, relays, or microcontroller projects without slowing your application. Two independent channels handle data flow so communication stays full duplex, making it suitable for command-and-response traffic or continuous data streaming.

Technicians often keep the IC1157A in a field toolkit when servicing older machinery used in industry that still exposes TTL headers. Product developers can place it on the bench to link a PC running a terminal program to an embedded prototype. System integrators use it inside control panels where space is limited, thanks to a housing that slips neatly beside existing wiring.

Installation is straightforward: plug the DB9 male connector into the RS-232 port, wire the TTL side to the target, and set your software to the desired baud rate. No jumpers, firmware, or special drivers are required.

Highlights:

• Converts RS-232 signals to 5 V TTL and back on two channels for full bidirectional communication
• Operates at data rates up to 115 kbps for responsive control and monitoring
• Draws power directly from the RS-232 interface, removing the need for an external supply
• Housing that fits comfortably inside control cabinets or portable service kits
• Ready to use without configuration, ideal for field service, prototyping, or permanent installations