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Telephone cable - how many pairs?
- Thread starter Mr_T25
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They're not twisted tightly like Cat5e, but they will be twisted (8 twists per metre), otherwise they wouldn't be able to call them 'pairs', it would just be called 4 core cable, which is what alarm cable is, as it's cheaper to manufacture a cable with parallel conductors than twisted.
Gaz
Hi
Now having received a few hundred meters of the correct cable, how best would I design the cable run to each room? Like ethernet cable, should I take each room down to a central cupboard rather than running it in a serial circuit from room to room?
Now having received a few hundred meters of the correct cable, how best would I design the cable run to each room? Like ethernet cable, should I take each room down to a central cupboard rather than running it in a serial circuit from room to room?
For telephones ? If your going to fit a small pabx , all back ,if just one common phone line daisy chain , you could pick up noise on the line if you have loads of star wiring ( all back to one point) I have seen this happen.
Why is it called star wiring?
I believe the phone line has a REN capacity of 4. If I wanted more phones on there (theoretically), is it just a case of ensuring that the phone is powered by the mains because there will be insufficient current within the line to power more than 4 phones otherwise?
I believe the phone line has a REN capacity of 4. If I wanted more phones on there (theoretically), is it just a case of ensuring that the phone is powered by the mains because there will be insufficient current within the line to power more than 4 phones otherwise?
REN Ringer Equivalence Number
The bells were designed to be rung using AC current ( hence the capacitor in the system to allow only AC to reach the bells ). Too many bells meant too much AC current flowing and this could result in the exchange "ring tripping" ( false answer ) on the AC current instead of waiting until DC current started to flow as a result of the handset being picked up to answer the call.
The speech circuits are powered by DC from the telephone exchange, typically 50 volts when the line is not in use and between 8 to 12 volts ( at the phone ) when the handset is lifted
If one only has 4 bells ( or equivalent AC load ) there is no limit to how many phones can be connected to the line. In most cases ( except on very long lines ) two or three phones can be used at the same time on one line before speech volume and quality is noticably degraded.
The bells were designed to be rung using AC current ( hence the capacitor in the system to allow only AC to reach the bells ). Too many bells meant too much AC current flowing and this could result in the exchange "ring tripping" ( false answer ) on the AC current instead of waiting until DC current started to flow as a result of the handset being picked up to answer the call.
The speech circuits are powered by DC from the telephone exchange, typically 50 volts when the line is not in use and between 8 to 12 volts ( at the phone ) when the handset is lifted
If one only has 4 bells ( or equivalent AC load ) there is no limit to how many phones can be connected to the line. In most cases ( except on very long lines ) two or three phones can be used at the same time on one line before speech volume and quality is noticably degraded.
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