sichermn@beach.csulb.edu (Jeff Sicherman) (03/23/91)
Is it feasible to run a LAn sharing cabling in a 50-conductor telco-type cable that is currently being used with a 1A2 phone system. What speed limitations are there. ANy products more compatible with this than others ? Any suggestions, critiques, experiences, etc. would be appreciated.
cmilono@netcom.COM (Carlo Milono) (03/26/91)
In article <1991Mar22.221831.17898@beach.csulb.edu> sichermn@beach.csulb.edu (Jeff Sicherman) writes: > > Is it feasible to run a LAn sharing cabling in a 50-conductor telco-type >cable that is currently being used with a 1A2 phone system. What speed >limitations are there. ANy products more compatible with this than others ? >Any suggestions, critiques, experiences, etc. would be appreciated. 10BASET allows for this with some caveats. 1A2 is an analog-based system with A-leads and lamps, with the strongest circuits being the Tip and Ring under ringing voltage. Such systems run on 75-pair and 100-pair cables as well (ye old call directors). 10BASET was set to allow for such cable runs and is quite immune to any telephonic voltages, however, it is not wise to mix multiple LAN runs in a single 25-pair cable run due to interference with one another, but a single 10MBps works fine with 1A and 1A2 Key equipment, with a limit of 100 meters. 10BASET is 10BASET, but some vendor's products are a bit more susceptible to external EMI/RFI than others, but the spec is a spec...some just exceed it a bit. HOWEVER: not all wire is created equal and some runs may have weird impedance characteristics - watch out for bridged cables (with bridge clips), and CPC adapters (Cable-Phone-Cable) where multiple sets share a single cable. -- +--------------------------------------------------------------------------+ | Carlo Milono: cmilono@netcom.apple.com or apple!netcom!cmilono | |"When a true genius appears in the world, you may know him by this sign, | |that the dunces are all in confederacy against him." - Jonathan Swift | +--------------------------------------------------------------------------+
pat@hprnd.rose.hp.com (Pat Thaler) (04/10/91)
In comp.dcom.lans, cmilono@netcom.COM (Carlo Milono) writes: In article <1991Mar22.221831.17898@beach.csulb.edu> sichermn@beach.csulb.edu (Jeff Sicherman) writes: > > Is it feasible to run a LAn sharing cabling in a 50-conductor telco-type >cable that is currently being used with a 1A2 phone system. What speed >limitations are there. ANy products more compatible with this than others ? >Any suggestions, critiques, experiences, etc. would be appreciated. 10BASET was set to allow for such cable runs and is quite immune to any telephonic voltages, however, it is not wise to mix multiple LAN runs in a single 25-pair cable run due to interference with one another, but a single 10MBps works fine with 1A and 1A2 Key equipment, with a limit of 100 meters. Right on phone service, the 10BASE-T standard was designed to allow running in cables with analog phone services while meeting its bit error rate objective of less than 1 in 10^9. The statement about not mixing multiple LAN runs is not correct for 10BASE-T which was also designed to allow multiple 10BASE-T connections in the same bundle upto fully loading the bundle with 10BASE-T. (Noise in a > 25 pair cable will be pretty much the same as in 25 pair.) 10BASE-T operates at 10Mbps. The limitations of operating on twisted pair are dependent on the total system design (encoding method, filtering, equalization, etc) and not just data rate. Pat Thaler