1. Jacks and Plugs There are two sizes of patch bay jacks and plugs. The bays used with approximately 1/4" diameter plugs are known as Longframe, while the bays used with 11/64" diameter plugs are known as Bantam, TT, or Tiny Telephone. A Whirlwind Longframe bay has 24 jacks per row providing 48 patch points (also referred to as a 48 point patch bay). A Whirlwind TT bay has two rows of 48 jacks each, providing 96 patch points. 2. Wiring The convention for patch bay wiring is that they are configured with two rows of jacks, one above the other, with the top row wired to equipment outputs, and the bottom row wired to equipment inputs. The jacks are numbered in a standard left to right,top to bottom scheme (Top Row: 1-24 LONGFRAME or 1-48 TT, Bottom Row: 25-48 LONGFRAME or 49-96 TT). 3. Normalling Typically patch bays are wired so that with no patch cables inserted, each jack in the top row is "normally" connected to the jack immediately below it in the bottom row. By planning your wiring in advance, this arrangement will automatically connect the outputs of equipment (wired to the top row jacks) to the inputs of other equipment (wired to the bottom row jacks) in the most often used configuration. Then, when you need to do something special, you can insert patch cords and change the way signals are connected. There are two common forms of normalling: HALF NORMAL and FULL NORMAL. HALF NORMAL (HN) The top row jacks are connected to the corresponding bottom row jacks through switching contacts in the bottom jack. When you plug a patch cord into the top jack on an HN patch bay, the output signal wired to that top jack stays connected to the jack below it. At the same time, the output signal from the top jack is now connected to your patch cord and can be plugged into another input jack on the patch bay or connected directly to another piece of gear. The result is one output going to two inputs. Only when you plug a patch cord into a bottom row (input) jack on an HN patch bay is the "normal" connection disconnected between it and the jack above it . FULL NORMAL (FN) uses switching contacts in both rows of jacks. Plugging a cord into either the top or bottom row jack of a full normalled bay disconnects the "Normal" signal flow from the top to bottom jacks. 4. Grounding Grounding throughout a patch bay wiring system can be a complicated issue. To keep ground-loop induced hum from entering your system, it is important to decide on a uniform method of interconnecting equipment chassis grounds and audio shields. Individual situations may require different solutions regarding what type of grounding configuration will be most effective. Consequently, we offer four standard configurations for the termination of shields at the patch bay. These options are designated ST, SB, SS, or SN. The ST (Shields Terminated) designation indicates that the shield for each wire will be terminated only at the jack terminal. Shield wires do not interconnect from jack to jack. The SB (Shields Bussed) designation indicates bussed shields. Each row of jacks has a buss bar that connects all shield connections from that row together and is brought out with a single ground-wire lead. The SS (Shields Strapped) designation indicates strapped shields, meaning that the shield of each top row output jack is connected to the shield of the input jack directly below it. This connection remains whether or not patch cables are inserted into the jacks. The SN (Shields Normalled) designation requires a special patch bay using jacks with shield normalling switch contacts. These contacts allow the shield to be either half or full normalled from a jack in the top row to the jack immediately below it. This is the least common of these grounding schemes. 5. Termination The wiring to connect the patch bay to your equipment can be done in several ways: Cables can be pre-wired to the jacks in your patch bay and left blunt cut or trimmed and prepped as required. Connectors can be soldered onto "cable tails" (shielded pair wires soldered to the jacks in your patch bay and long enough to reach your equipment) for direct connection to your gear. It is possible to specify the ground scheme at the equipment connectors. For individual XLRs, 1/4", or RCA connectors, the shield is connected to the appropriate terminal of the connector. The GL (Ground Lift) designation indicates that the shield is left disconnected at the connector. Inline or chassis multipin connectors can be wired to short lengths of cable soldered to the jacks in your patch bay. You then connect cables between these connectors and your equipment. This arrangement allows you to easily remove the patch bay from your system while leaving the basic wiring from your equipment to the patch bay intact. Whirlwind MPB punch blocks are available pre-wired to the jacks of your patch bay for rapid, solderless "insulation displacement" field termination of wires running to your equipment. 6. Cleaning Whirlwind recommends cleaning patch bays by inserting a clean plug five or six times into a jack. The use of chemical cleaners or compressed air is not recommended. Although it may be possible to construct a catalog number from the following table, it is ALWAYS better to make a drawing of your requirements or download the patch bay worksheets available below. Refer to the table to get an idea of what is available and what options should be considered and specified to fulfill your own individual requirements.

The following patch bay worksheets in PDF or Excel format are available for download: 48 point longframe worksheet (PDF-39KB) 96 point TT worksheet (PDF-44KB) 48 and 96 point TT workbook - Excel (XLS-54KB)

PDF requires Acrobat Reader ==>

Catalog Number 1 2 3 4 5 Match number to chart

BAY

1

WLF482 - 48 point longframe 2 rack spaces

WTT961 - 96 point Bantam 1 rack space

NORMALLING

2

NN - no normal connections

HN - half normal wiring

FN - full normal wiring

GROUND SCHEME

3

ST - shields connected at jack only

SS - shield strapped from top jack to the one below it

SB - all top row shields are bussed together, all bottom row shields bussed together

SN - shield half or full normalled via special jacks in top and bottom rows (non-standard)

CABLE AND LENGTH

4

IP - individual pieces of 8451, 9451, 1266A, etc

MP - Whirlwind standard multipair with heatshrunk fanouts

IJ - individually jacketed multipair

TERMINATION

5

W4C(O) - Whirlwind W4 chassis: wired in Output configuration

W4C(I) - Whirlwind W4 chassis: wired in Input configuration

W4I(O) - Whirlwind W4 inline: wired in Output configuration

W4I(I) - Whirlwind W4 inline: wired in Input configuration

T - For 96 point patch bays wired to 1-48 top row

B - For 96 point patch bays wired to 49-96 bottom row

S - For 96 point patch bays wired to 24 top row jacks and 24 corresponding bottom row jacks

For 96 point patch bays, with two MASS connectors or multiples of Elco, please apply the appropriate suffix to the multipin indicated above:

E2CM - Elco chassis male wired to 24 jacks

E2CF - Elco chassis female wired to 24 jacks

E2IM - Elco inline male wired to 24 jacks

E2IF - Elco inline female wired to 24 jacks

T - Apply as in W4 above with jack # designations

B - Apply as in W4 above with jack # designations

S - Apply as in W4 above with jack # designations

MPB58 - Whirlwind MASS Punch Block (1 per 48 jacks)

MPB24 - Whirlwind MINI Punch Block (1 per 24 jacks)

BC - Blunt cut cable, Brady markers for IP; MP, and I J use color or number code

BP - Blunt cable prepped for punchdown in the MPB termination - specify type

F2 - Female WI3F XLR wired pin 1 shield, pin 2 to the tip of the jack, pin 3 to the ring of the jack

F3 - Female WI3F XLR wired pin 1 shield, pin 3 to the tip of the jack, pin 2 to the ring of the jack

M2 - Male (WI3M) XLR wired pin 1 shield, pin 2 to the tip of the jack, pin 3 to the ring of the jack

M3 - Male (WI3M) XLR wired pin 1 shield, pin 3 to the tip of the jack, pin 2 to the ring of the jack

S - TRS 1/4" plug wired tip to tip, ring to ring, shield to shield

U - TS 1/4" plug wired tip to tip, ring and shield tied at plug

R - Male RCA phono plug wired tip to tip, ring and shield tied at plug

NOTE: GL (Ground Lift) suffix can be applied to termination options F2, F3, M2, M3, S, U, and R above. This suffix will designate that the shield is not connected to any pin in the connector. Examples: F3GL, M2GL, UGL, etc. The shield is still connected at the patch bay jack.