Specifications

October 8, 2003 Networking Alpha Signs (9700-0112C)
8 Wired networks
Wired networks
Serial—preliminary information
With serial connections, either RS232 or RS485 cable is used. Selecting which cable to use depends on the
distance from the PC to the sign:
All cables should be kept as short as possible to reduce interference and quicken the process of sending the
data. See your sign’s installation manual for maximum serial speed.
NOTE: Because it will not create toxic fumes, plenum cable (pn 1088-8002 and pn 7122-0283) should be used
anytime there is either a potential for fire or where cabling is run near common ventilation, such as in
the ceiling, near cold air returns, or as local electrical codes require. Do not use standard RS485 cable
(pn 1088-8624 and pn 1088-8636) in these cases — use only plenum cable.
On some signs, an internal jumper must be set to either RS232 or RS485 depending on the cabling the sign is
using (see “Appendix D—Setting the RS232/RS485 jumper” on page 53 for additional information). Also, some
signs may need to be terminated depending upon which type of network and the number of signs you are using
(see “Appendix B—End-of-line termination” on page 50 for additional information).
Maximum drops
In an RS485 network, the maximum number of connections (or “taps”) to a network is 32. Taps are also called
network drops and they can include PCs, signs, servers, and so on. If more than 32 taps are required, use an RS485
repeater box, which boosts the electrical signal. Note that the repeater box itself counts as a tap.
NOTE: Star networks, in which a converter box is central to all signs on a network in a star pattern
, are not
recommended.
Cable length
In an RS485 network, signs should connect to Modular Network Adapters, similar to phone jacks, with a
recommended adapter-to-cable length of 1 foot. This length provides optimum hardware operation and data
transmission integrity. However, the 8-foot length will work for most installations and can still be used.
Distance from PC to sign Recommended cable
Less than 50 feet RS232 cable
Greater than 50 feet but less than 4000 RS485 cable*
*Additional hardware is needed to accommodate the longer distance.
Alpha signAlpha sign
Alpha sign
32 drops maximum
8-foot maximum
(1-foot recommended)
Drop 1
Drop 2
Drop 3
Drop 4
Drop 5
RS485