Cable Distance Limitations
The following specifications provide allowable cabling distances for the following devices:
● Single-Line Voice Terminals
● Multiline Voice Terminals
● Data Terminals (RS-232) Connected to Asynchronous Data Units (ADUs).
Single-Line Voice Terminals
SUPPORTING 24-GAUGE WIRE
CIRCUIT (0.5106 mm)
PACK
FEET
METERS
ZTN78
2,000
610
TN742 *
24,000 7,320
TN742 †
15,000
4,500
* 2500-type voice terminals
† 7101-type voice terminals
IN BUILDING
SINGLE-LINE < 2000 FEET ZTN78
VOICE TIP RING LINE
TERMINAL
CP
EXTENDED STATION
OR
OUT-OF-BUILDING
OR
> 2000 FEET *
TN742
OFF-PREMISES ANALOG LINE +
SINGLE-LINE
CP
VOICE
TERMINAL
* UP TO 24,000 FEET. TIP/RING LOOP RESISTANCE FROM
SYSTEM CABINETS (INCLUDING VOICE TERMINAL) MUST
NOT EXCEED 1300 OHMS.
+ FIVE SINGLE-LINE VOICE TERMINALS
WHEN USING THE TN-742, HOWEVER, ONLY TWO MAY BE
OFF-HOOK AT ONE TIME.
Figure 5-1. Single-Line Voice Terminal Allowable Cable Distances
5-6