Model ASC24T: Fast Async RS232 <=> RS485 automatic converter with removable terminal strip, edge mounted LED indicators, and transient protection.

• Fast auto TX-enable RS232 <=> RS485 interface converter for 2-wire, half-duplex communications, in point-to-point or multi-drop communications networks, at distances up to 4000 ft. and data rates up to 115.2Kbps. Rev. B and Rev B1 boards have larger LED indicators, improved timing, a "loop-back" jumper, and an extended temperature range of -40C to +85C.

GENERAL DESCRIPTION and TYPICAL APPLICATIONS:

The ASC24T is a fast Async bi-directional RS232 <=> RS485 interface converter for 2-wire, half-duplex applications, with an automatic TX enable circuit, that will operate at data rates up to 115.2Kbps. The unit has jumpers for bias, termination, RS232 DTE/DCE selection, and a setting for fast responding RS485 devices. The unit has edge mounted LED indicators, a removable screw terminal connector, and uses an SP485REP limited slew rate transceiver (1/4 unit load) with built-in transient protection.

The ASC24T is designed for office and/or industrial applications (non-isolated), and provides superior characteristics/features normally found only on more expensive units. Can be used for point to point, or multi-drop 2-wire systems.
 

Download:
	ASC24TrevB1.pdf	Converter schematic/physical Rev. B1
	ASC24TrevB.pdf	Converter schematic/physical Rev. B
	ASC24TrevA.pdf	Converter schematic/physical Rev. A

Click image for full-size photograph:

PHYSICAL PROPERTIES and FEATURES:
 

RS232:	3-wire interface to RJ11/12 Connector (TX, RX, Common).
RS485:	Removable screw terminal (TX/RX+, TX/RX-, Common).
Power:	2.1mm center positive "Barrel" connector (8-12VDC), linear regulator.
LEDs	Power(YEL), TX-RS485(RED), and RX-RS485(GRN).
Bias:	620 Ohm pull-up and pull-down (jumper selectable).
Termination:	120 Ohm (jumper selectable).
Special:	Jumper selection for fast responding RS485 devices.
Protection:	Up to 400W typical per SN75LBC184P specification.

SPECIFICATIONS:
 

Distance:	RS485 up to 4000 ft. (1250 meters)
Operation:	2-wire half-duplex RS485 Data.
Format:	Asynchronous data with any combination of bits, parity, stop.
Speed:	Up to 115.2Kbps (slew limited driver).
Temperature:	0-65C (32-150F) ambient.
Humidity:	10-90% non-condensing.
Voltage:	8-12VDC.
Power:	Under 1/2 Watt(typical) + external load.
Size:	2.50" X 2.00" X 0.9" (PC Board), with connectors: 2.50" X 2.25".
Mounting:	4-Holes at 2.00" X 1.50" (built-in standoffs for #6 hardware).

OPTIONS AND ORDERING INFORMATION: (Model ASC24T)
 

ASC24T:	$45.00 ea. (Circuit board only)
Enclosure:	$8.00 ea. (Small)
Cable:	$7.50 ea. (RS232, 7 ft., Specify DB9F-7 or DB25F-7)
Supply:	$7.50 ea. (9VDC @ 200/300 mA wall power supply)

*ASC24T with all options (DB9F cable): ASC24T-B9FPS @ $68.00 ea. (Qty. 1-9)