Pro Switching System II Chassis, RS-232, RS-530, X.21, V.35

Chassis-mounted switching and patching system for RS-232, RS-530, X.21, and V.35 data communications.

Daisychain up to 9901 fully populated chassis units to control and manage up to 158,416 A/B interface cards.

Multiple programmable alarms keep you abreast of network conditions.

Easy-to-use Management Control Software makes on-screen control a snap.

For PLC control of all gang-switching functions, install a Manual Contact Closure Card. 

Redundant 110-/220-VAC power options.

Front Interface Cards offer A/B switching and patching capabilities. Order low-cost Universal Serial Cards for faster switch-only capabilities.

Order cards, management software, and test cords separately.

With the modular Pro Switching System II, you can switch individual or multiple RS-232, RS-530, X.21, or V.35 circuits from a single console.


The Pro Switching System II is a chassis-mounted switching and patching system for RS-232, V.35, RS-530, and X.21 communications. It enables you to daisychain up to 9901 chassis to control and manage an incredible 158,416 A/B interface cards from a single console!

You can switch individual circuits, all 16 circuits in a chassis, or a group of user-defined circuits via remote console commands or automatically upon alarm. Use front-panel push buttons to switch individual circuits or to gang-switch an entire chassis. Or disable manual switching capabilities with a console command. We even offer a contact closure card that enables you to use a programmable logic controller (PLC) to direct the circuit switching.

Meet the switch gang.
The core of the Pro Switching System II is its chassis. Each Pro Switching System II Chassis supports 16 interface cards.

For additional circuits, daisychain multiple chassis. You can populate up to 16 Front Interface Cards (SM906C–909C) or Universal Serial Cards (SM930C–SM934C) in each slave chassis within a daisychain configuration. The master chassis can be populated with up to 16 of these cards plus one Terminal Display Card (SM903C, SM905C).

The chassis also requires a Management Control Card (SM902C). You can also equip your chassis with one or two Power Supply Modules (SM950A, SM950A-220). If one module goes down, the other kicks in to keep your data moving.

The straight deal on the Front Interface Cards (SM906C–909C).
The chassis holds RS-232, RS-530, X.21, or V.35 Front Interface Cards. The cards feature a switchable A/B circuit, a common RS-232 or V.35 cable connection, plus five signal-monitoring LEDs.

With up to nine alarm options, you can configure each RS-232, V.35, and RS-530 circuit individually for up to eight alarms on the presence or absence of Physical Layer signals. You can configure each X.21 circuit individually for up to six programmable alarms.

The cards install in the front of the Pro Switching System II chassis.

Universal Serial Cards for low-cost A/B switching! (SM930C–SM934C)
If you don’t need patching capabilities and want economical A/B switch-only capabilities and faster transfer speeds (100 Mbps), order up to 16 of these modules. These universal cards support RS-232, V.35, RS-530, X.21, 10BASE-T, and analog RJ-11 or RJ-45 communications, and they differ only in the interface adapters shipped with them.

With their latching relay feature, the Universal Serial Cards forward all traffic in a power failure and, when used as a copper path, operate independenty of speed and protocol. What’s more, there’s no complicated programming.

The Universal Serial Cards install in the front of the Pro Switching System II chassis and can be mounted alongside the Front Interface Cards.

What A/B switching gives you.
The Pro Switching System II cards are equipped with three ports that link to A, B, and Common paths. Switch between ports, for instance, when you need to reroute a path from a failed attached device to a device or circuit that’s operational. To switch, you only need to press a button on the mounted card. LEDs inform you of your selected switch position.

Or, if you prefer, control the card via an attached ASCII terminal or GUI. Use the Management Control Software (SM912A) and a Management Control Card (SM902C) or a Terminal Display Card (SM903C, SM905C) installed in the chassis. With this setup, you can program the system to switch circuits automatically at a specified time.

For example, use an RJ-11 Universal Serial Card (SM933C) in an office application where you need to redirect incoming calls at a certain time from the one desk to another. You can also control a group of the cards in a gang-switch capacity.

Gang switch using a Manual Contact Closure Card (SM916C)
With the Pro Switching System II Manual Contact Closure Card, you can provide both manual and contact closure gang-switching capabilities to your system. By patching a programmable logic controller (PLC) to the straight-through "control" connector, you can use the PLC to switch all circuits in the chassis from A to B and back again automatically.

Use the Card with a PLC to close contacts, and to disable specific cards seated in the chassis using its DIP switches. A toggle button enables you to manually reverse all switch positions in the master chassis.

Easy management with the Management Control Card (SM902C) and Software (SM912A)
The master chassis requires a Management Control Card to work with the Management Control Software (SM912A) to provde an easy-to-use GUI interface.

The software’s interface displays on-screen alarm conditions with a date and time stamp. A color-coded signal also shows the status of any circuit in the network, and you can view signal status for an entire chassis.

Control terminals with Terminal Display Cards (SM903C, SM905C, SM916C))<

How to order. (All components are sold separately.)

First, order the Pro Switching System II Chassis.

RS-232, V.35, RS-530, X.21: SM900A.

V.35 Only: SM901A.

Next, order one or two Power Supply Modules.

110-VAC: SM950A.

220-VAC: SM950A-220.

Then, select a Management Control Card, a Terminal Display Card, or a Manual Contact Card for your master chassis.
Management Control Card for RS-232, V.35, RS-530, X.21: SM902C.
Terminal Display Cards

RS-232, V.35, RS-530, X.21: SM903C.

V.35 Only: SM905C.

Manual Contact Closure Card: SM916C.

Next, choose interface cards.
Front Interface Cards

RS-232: SM906C.

V.35: SM907C.

RS-530: SM908C.

X.21: SM909C.

Universal Serial Cards

RS-232 (DB25): SM930C.

DB9 Serial: SM931C.

DB15 Serial: SM932C.

RJ-11 (4-Wire): SM933C.

RJ-45 (8-Wire): SM934C.

For empty slots, order Blank Covers.

Interface Blank Cover: SM910C.

Power Supply: SM911C.

To manage the System, order Management Control Software.

Software: SM912A.

Optional Test Cords.

RS-232/RS-530: SM917.

V.35: SM918.