advanced search

Datacom Office Wiring: Recommended Procedures

Apr 1, 1999 12:00 PM, By Paul Rosenberg, Consulting Datacom Editor

Voice and data wiring essentially involves installing cable and connecting equipment: the same things most of us have been doing for decades. But there are some significant differences related to system performance and required installation methods.

It's not difficult work, and it usually pays well." That's what we typically hear about wiring offices for voice and data. To become successful, you must first learn basic installation mechanics. Let's look at a few diagrams describing the basic system structure and talk about some of these special areas of concern.

EIA/TIA standards: your guides to cabling layout. Your primary source of information is the general standard for structured cabling systems. This is EIA/TIA 568 (Commercial Building Telecommunications Wiring Standard). It includes later revisions, such as 568A and 568B. There are other associated standards, such as EIA/TIA 569 (Commercial Building Standard for Telecommunications Pathways and Spaces) and TIA/EIA 606 (Administration Standard for the Telecommunications Infrastructure of Commercial Buildings). Note: These standards are not codes. Therefore, you're not required to follow them when you install communication cabling. But if you want to install structured cabling properly, you should follow them.

The main cross-connect is where the entire building network connects to outside telephone lines or some other type of long-distance circuit.

The horizontal runs are similar to branch circuits, running from a patchpanel in the telecom closet to the wall outlet. A patch cord runs from the outlet to the computer.

Voice cabling basics. While voice circuits don't require the same high-quality cabling as computer networks, installers frequently wire them with Cat. 5 cables. This is because most contractors find it easier to standardize on one type of cable for both voice and data, rather than keeping track of two types. The cost difference is minimal.

"UTP" stands for unshielded twisted pair cable. "PBX" stands for private business exchange (the main telephone equipment). Without a PBX, customers would have to install a great number of outside telephone lines; one for each extension. Instead, the PBX switches several extensions on a few outside (trunk) telephone lines. It may also provide intercom, music-on-hold, and many other features.

Always use caution. When installing voice or data cabling, follow these guidelines:

• Don't forget about fire stopping. Note where the fire barriers are in the structure, and make sure you make proper allowances for crossing them.

• Make sure you protect your cables during the construction process (while you're not there). This is critical in situations where there'll be a long time between your cable installation and installing of jacks. In such instances, it's up to you to protect your cables any way you can. If you don't, they may pull away or twist by accident. You won't see this damage to the cables until you test them.

• Leave enough extra cable at each outlet point. The recommended slack lengths are a minimum of 3 m (almost 10 ft) in the telecommunications closet for both twisted-pair and fiber cable, 1 m (a little over 3 ft, 3 in.) for fiber, and 30 cm (almost 1 ft) for twisted-pair cable at the outlet. (Notice when you move from power wiring to data cabling, the units of measurement switch from standard to metric.)

• Trimming data cabling is essentially the same as trimming power wiring (strip the cables, install the devices and plates, etc.) except a lot more testing is required. When trimming power wiring, we generally test by flipping a switch or hitting the outlet with a voltage tester. Either power is present, or it's not. Testing data cabling is not so simple. Remember, you need to test not only for the presence of the signal, but also for its quality.

Want to use this article? Click here for options!

© 2012 Penton Business Media, Inc.

---

Acceptable Use Policy blog comments powered by Disqus

Browse Back Issues Select an Issue November 2011 October 2011 September 2011 August 2011 July 2011 June 2011 May 2011 April 2011 March 2011 February 2011 January 2011 December 2010 November 2010 October 2010 September 2010 August 2010 July 2010 June 2010 May 2010 April 2010 March 2010 February 2010 January 2010 December 2009 November 2009 October 2009 September 2009 August 2009 July 2009 June 2009 May 2009 April 2009 March 2009 February 2009 January 1, 2009 December 2008 November 2008 October 1, 2008 September 2008 August 2008 July 2008 June 1, 2008 May 2008 April 2008 March 2008 February 2008 January 2008 December 2007 November 2007 October 2007 September 2007 August 2007 July 2007 June 2007 May 2007 April 2007 March 2007 February 2007 January 2007 December 2006 November 2006 October 2006 September 2006 August 2006 July 2006 June 1, 2006 May 1, 2006 April 2006 March 1, 2006 February 2006 January 2006 December 2005 November 2005 October 2005 September 2005 August 2005 July 2005 June 2005 May 2005 April 2005 March 2005 February 2005 January 2005 December 2004 November 2004 October 2004 September 2004 August 2004 July 2004 June 2004 May 2004 April 2004 March 2004 February 1, 2004 January 1, 2004 December 1, 2003 November 1, 2003 October 1, 2003 September 1, 2003 August 1, 2003 July 1, 2003 June 1, 2003 May 1, 2003 April 1, 2003 March 1, 2003 February 1, 2003 January 1, 2003 December 1, 2002 November 1, 2002 October 1, 2002 September 1, 2002 August 1, 2002 July 1, 2002 June 1, 2002 May 1, 2002 April 1, 2002 March 1, 2002 February 1, 2002 January 1, 2002 December 1, 2001 November 1, 2001 October 1, 2001 September 1, 2001 August 1, 2001 July 1, 2001 June 1, 2001 May 1, 2001 April 1, 2001 March 1, 2001 February 1, 2001 February 1, 1995 January 1, 2001 December 1, 2000 November 1, 2000 October 1, 2000 September 1, 2000 August 1, 2000 July 1, 2000 June 1, 2000 May 1, 2000 April 1, 2000 March 1, 2000 February 1, 2000 January 1, 2000 December 1, 1999 November 1, 1999 October 1, 1999 September 1, 1999 August 1, 1999 July 1, 1999 June 1, 1999 May 1, 1999 April 1, 1999 March 1, 1999 February 1, 1999 January 1, 1999 December 1, 1998 November 1, 1998 October 1, 1998 September 1, 1998 August 1, 1998 July 1, 1998 June 1, 1998 May 1, 1998 April 1, 1998 March 1, 1998 February 1, 1998 January 1, 1998 December 1, 1997 November 1, 1997 December 1, 1996 November 1, 1996 October 1, 1996 September 1, 1996 August 1, 1996 July 1, 1996 June 1, 1996 May 1, 1996 April 1, 1996 March 1, 1996 February 1, 1996 January 1, 1996 December 1, 1995 November 30, 1995 November 1, 1995 October 1, 1995 September 1, 1995 August 1, 1995 July 1, 1995 June 1, 1995 May 1, 1995 April 1, 1995 March 1, 1995

browse e-newsletters