Re: The difference between crossover and rollover cable
On Sat, 9 Sep 2000, Alex Lee wrote: > Hello Jay, > > Two stupid questions : > (a) Why is that a 56 K crossover pin-out (is this the correct term ?) > differs from a T1 ? Different telco standards. No real reason, they just chose to use different pairs. T-1 is an RJ-48 standard, and 56K is an RJ-45. Note that many people mistakenly refer to any 8-pin modular connector as an "RJ-45". This is not technically accurate. The manner in which the connector is used determines its RJ-number. "RJ-nn" is an FCC standard for "Registered Jack", describing interfaces to the telephone network in Part 68 of FCC Rules. An 8-pin modular connector by itself isn't an RJ-anything until it is wired to a network. > (b) What is the purpose of using a 56K or T1 crossover cable ? Anywhere you have a physical protocol that uses one physical wire or pair for transmitting and another for receiving there may be the need to connect two devices directly without an intermediate medium. A 56K or T1 crossover would be used to connect two CSUs for a lab or short-haul connection. It's the same principle as an ethernet crossover or a null-modem for RS-232. The signal originating outbound on one side is connected to the input expecting a signal on the other side, and vice-versa. > Can you give me links so that I can get some more details info ? Thanks. http://www.cisco.com/univercd/cc/td/doc/product/access/acs_mod/cis3600/marcabl.htm More Cisco pinouts than you'll ever want to know about. The docs for each router series have a section on cables used with that particular box. The URL above is for a 3600 which should cover most of them. -- Jay Hennigan - Network Administration - [EMAIL PROTECTED] NetLojix Communications, Inc. NASDAQ: NETX - http://www.netlojix.com/ WestNet: Connecting you to the planet. 805 884-6323 **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
RE: The difference between crossover and rollover cable
Crossover is where you cross 1 with 3 and 2 with 6. 1 --- 3 2 --- 6 3 --- 1 4 --- 4 5 --- 5 6 --- 2 7 --- 7 8 --- 8 Rollover is where you mirror all 8 wires, so 1 goes to 8, 2 goes to 7, etc... 1 --- 8 2 --- 7 3 --- 6 4 --- 5 5 --- 4 6 --- 3 7 --- 2 8 --- 1 Hth, Ole Ole Drews Jensen Systems Network Manager CCNA, MCSE, MCP+I RWR Enterprises, Inc. [EMAIL PROTECTED] http://www.insync.net/~drews/ccnp -Original Message- From: Lists Wizard [mailto:[EMAIL PROTECTED]] Sent: Friday, September 08, 2000 11:56 PM To: 'Cisco group study'; [EMAIL PROTECTED] Subject: The difference between crossover and rollover cable Hi , Can any body show me if there is a difference in definition between crossover and rollover cables. Thanks __ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The difference between crossover and rollover cable
Try this link. http://www.cisco.com/univercd/cc/td/doc/product/dsl_prod/c1400/icg/cables.htm#xtocid214333 Rick On Fri, 8 Sep 2000, Lists Wizard wrote: >Date: Fri, 8 Sep 2000 22:56:01 -0600 >From: Lists Wizard <[EMAIL PROTECTED]> >To: 'Cisco group study' <[EMAIL PROTECTED]>, [EMAIL PROTECTED] >Subject: The difference between crossover and rollover cable > >Hi , > >Can any body show me if there is a difference in definition between >crossover and rollover cables. > > >Thanks > > >__ >Do You Yahoo!? >Talk to your friends online with Yahoo! Messenger. >http://im.yahoo.com > >**NOTE: New CCNA/CCDA List has been formed. For more information go to >http://www.groupstudy.com/list/Associates.html >_ >UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html >FAQ, list archives, and subscription info: http://www.groupstudy.com >Report misconduct and Nondisclosure violations to [EMAIL PROTECTED] > **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
Re: The difference between crossover and rollover cable
On Fri, 8 Sep 2000, Lists Wizard wrote: > Can any body show me if there is a difference in definition between > crossover and rollover cables. Ethernet crossover: 1 - 3 2 - 6 3 - 1 6 - 2 T-1 crossover: 1 - 4 2 - 5 4 - 1 5 - 2 56K crossover: 1 - 7 2 - 8 7 - 1 8 - 2 Rollover: 1 - 8 2 - 7 3 - 6 4 - 5 5 - 4 6 - 3 7 - 2 8 - 1 Where, looking into the jack, __ |12345678| |____| |__| A rollover will work for a 56K crossover in a pinch. Substituting a straight-through for a rollover gives a null-modem function for Cisco console aux and async ports. -- Jay Hennigan - Network Administration - [EMAIL PROTECTED] NetLojix Communications, Inc. NASDAQ: NETX - http://www.netlojix.com/ WestNet: Connecting you to the planet. 805 884-6323 **NOTE: New CCNA/CCDA List has been formed. For more information go to http://www.groupstudy.com/list/Associates.html _ UPDATED Posting Guidelines: http://www.groupstudy.com/list/guide.html FAQ, list archives, and subscription info: http://www.groupstudy.com Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
