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SBX20
ARCNET® Network Interface Module for Intel iSBX™ ™ ™ ™ ™ Compatible
INSTALLATION GUIDE
INTRODUCTION
The SBX20 series of ARCNET network interface modules (NIMs) links
single-board computers (SBCs) with the ARCNET local area network.
ARCNET is classified as a token-bus local area network (LAN) operating at
2.5 Mbps while supporting 255 nodes. Interfacing ARCNET to a host
computer usually requires a NIM which plugs into the host computer's bus.
In the case of single-board computers which have no bus, a NIM solution is
not possible. However, many SBCs have an on-board expansion slot which
conforms to Intel's iSBX Bus Specification. Using the SBX20 ARCNET
NIM, SBCs can now be linked to the ARCNET LAN via the iSBX
expansion socket.
The SBX20 ARCNET NIM is a compact, low power CMOS design, which
conforms to the single-wide iSBX Multimodule Board Outline with
variation (2.85" x 3.70"; 72mm x 93mm). However, the coaxial and fiber
connectors extend beyond the board outline and raise the maximum
component height of the SBX20 ARCNET NIM to 0.500" (12mm) instead
of the specified 0.400" (10mm) height.
There are several versions of the SBX20 ARCNET NIM. The SBX20-CXS
supports coaxial star configurations requiring external active or passive
hubs. The SBX20-CXB supports a multidrop or coaxial bus configuration
usually requiring no hubs. Other versions include the SBX20-FOG
which supports fiber optic cable with either ST or SMA connectors. The
SBX20-TPB supports multidrop twisted-pair cabling. The SBX20-485
supports backplane mode EIA-485 cabling, while the SBX20-485D supports
non-backplane mode EIA-485. The SBX20-485X supports transformer
coupled EIA-485.
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Summary of Contents for Contemporary Controls ARCNET SBX20 Series
- Page 1 SBX20 ARCNET® Network Interface Module for Intel iSBX™ ™ ™ ™ ™ Compatible INSTALLATION GUIDE INTRODUCTION The SBX20 series of ARCNET network interface modules (NIMs) links single-board computers (SBCs) with the ARCNET local area network. ARCNET is classified as a token-bus local area network (LAN) operating at 2.5 Mbps while supporting 255 nodes.
- Page 2 SPECIFICATIONS Environmental Operating temperature: 0°C to +60°C Storage temperature: -40°C to +85°C Data Rates 2.5 Mbps, 1.25 Mbps, 625 kbps, 312.5 kbps, 156.25 kbps Dimensions 2.85H" x 3.7"W x 0.5"D (72mm x 93mm x 12mm) Shipping Weight 1 lb. (.45kg) iSBX Bus Specification 142686-002 dated 3/81 Power Requirements...
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Page 3: Installation
INSTALLATION The SBX20 can be installed in any SBX compatible, 8 or 16-bit, expansion bus. To install the SBX20, remove the cover of the computer exposing the motherboard and bus connectors. Care should be taken when installing the SBX20 because both it and the exposed microcomputer motherboard are sensitive to electrostatic discharge. -
Page 4: Indicator Lights
Interrupts Both SBX interrupt request lines MINTR0 and MINTR1 are supported. Interrupts can be invoked at jumper location E3. To enable an interrupt, insert a jumper across a pair of posts corresponding to the desired interrupt. Only one interrupt can be selected; therefore, only one jumper is supplied. If no interrupts are desired, remove all jumpers at E3. -
Page 5: Field Connections
FIELD CONNECTIONS The SBX20 is available in several transceiver options. Each transceiver, which is matched to a particular cable type, is identified by a three-digit suffix appended to the model number. The capabilities of each transceiver differs. -CXS Coaxial Star There are generally two types of coaxial cables that are used with the -CXS transceiver, RG-59/u and RG-62/u. - Page 6 Passive hubs cannot be used with -CXB NIMs and we only recommend the use of RG-62/u coaxial cable for segments. Contemporary Controls (CC) also supplies BNC terminators and Tee connectors. Ask for BNC-TER and BNC-T respectively. One note of caution, there is a minimum cable length between nodes (6 feet).
- Page 7 termination. When this type of connection is tightened excessively, the fiber optic cable can break resulting in unreliable communications. Also, the degree of tightening affects the optimum throughput of the cable and causes attenuation. Depending upon the degree of tightening, fiber alignment can vary from the optimal coupling, thereby introducing some attenuation.
- Page 8 Transmitter power is typically measured at one meter of cable and, therefore, includes the loss due to at least one connector. The outputs vary so CC tests each device to ensure that a minimum output power is achieved. The output power also varies with core sizes. In general, larger cores launch more energy.
- Page 9 Figure 5. TPB NIMs are connected in a daisy-chain fashion with terminators inserted at both end NIMs. terminator required to terminate the end points of the bus segment. When terminating the screw terminal connector, install a 100 ohm, ¼ watt resistor across the unused terminals.
- Page 10 required to either the BALUN or -TPB port. Connect either of these devices to one of the end NIMs on the segment. This requires the removal of the terminator at that end. The BALUN or -TPS port provides the termination. -485 DC Coupled EIA-485 Backplane Mode The SBX20-485 supports DC-coupled, EIA-485, backplane mode communications.
- Page 11 drivers are enabled. Differential receivers typically switch at or near zero volts differential and are guaranteed to switch at +/-200 mv. Through the transition point, 70 mv of hysteresis will be experienced. Therefore, a positive bias of 200 mv or greater will ensure a defined state.
- Page 12 the connections to pins 3 and 4 at each end. Do not use this type of cable. Some modular cable is not even twisted. Be sure to use the proper cable. Refer to Table 4 and 5 for connector pin assignments. Termination Each end of the segment must be terminated in the characteristic impedance of the cable.
- Page 13 For EIA-485 DC operation, it is very important that all devices on the wiring segment be referenced to the same ground potential in order that the common mode voltage requirement (+/-7 Vdc) of the EIA-485 specification is achieved. This can be accomplished by running a separate ground wire between all PC computers or by relying upon the third wire ground of the power connector assuming that the DC power return is connected to chassis ground on the PC computer.
- Page 14 daisy-chain fashion leaving the end NIMs with vacant RJ-11 connections. On these NIMs insert a jumper at E1 on both -485X daughter boards to invoke 120 ohm termination resistors or leave the jumpers open and insert RJ-11 style passive terminators in each of the two vacant RJ-11 jacks. Refer to Figure 9 for the E1 jumper locations.
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Page 15: Need More Help Installing This Product
Technical Support. Warranty Contemporary Controls (CC) warrants its product to the original purchaser for one year from the product’s shipping date. If a CC product fails to operate in compliance with its specification during this period, CC will, at its option, repair or replace the product at no charge.
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