Black Box TL421A User Manual

4-Port RJ-45 Modem Splitter (RS-232 on RJ-45)

Split data from a single modem to four RS-232
DTEs.

Passive, non-powered. Operates transparent to data formats and speeds.

TL4 21A

Customer

Support

Information

Order toll-free in the U.S .: Call 877-877-BBOX (outside U.S. call 724 -746-5500)
FREE technical support 24 hours a day, 7 days a week: Call 724-746-5500 or fax

724-746-0746 • Mailing address : Black Box Corporation, 10 00 Park Drive, L awren ce,
PA 15055-1018 • Web site: www.blackbox.co m • E-mail: info @blackbox.com

4-Port RJ-45 Modem Splitter (RS-232 on RJ-45)

1. Specifications

Leads Supported — Pins 3, 4, 5, 7, and 8 connected straight through between the

Master and Ports1–4;
Pins 1, 2, and 6 “diode OR’ed” from Ports 1–4 to the Master port

Connectors — (1) single style RJ-45 socket connector (Master);
(1) quad-style RJ-45 connector (Ports 1–4)

Power — Non-powered; no power supply required

Size — 1"H x 2.3"W x 4.3"D (2.5 x 5.7 x 10.8 cm)

Weight — 0.25 lb. (0.11 kg)

2. Introduction

The 4-Port RJ-45 Modem Splitter (TL421A) is designed to allow multiple terminals to
share a single modem. This passive device is non-powered and transparent to data
formats, rates, and protocols. Data received from the modem is transmitted to all
attached terminal devices. Only one terminal device may send data to the modem at
a time. If more than one terminal device sends data at the same time, the data will
be corrupted. Connect the Master port to a DCE device, such as a modem, using an
RJ-45 straight-through cable and the appropriate RJ/DB adapter. All other ports,
labeled Port 1 through Port 4, connect to DTE terminal devices. When connected to
DTE devices, you don’t need crossover cables.

Page 2

724-746-5500 | blackbox.com