ATT System 25 Reference Manual
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TECHNICAL SPECIFICATIONS Indicator Lamp Signals The following lamp signals are provided at multiline voice terminal and ATL telephone line appearances:cordless LAMP SIGNALPATTERN (In Milliseconds)MEANING DarkOffInactive LightedOnActive Flashing500 on, 500 off; repeated Ringing Broken50 on, 50 off; repeated,Transfer/Conference Fluttering(gated on/off every 500 ms)in progress Wink350 on, 50 off; repeated Hold 5-11
TECHNICAL SPECIFICATIONS Port Specifications The following tables provide interface specifications for System 25 line and trunk port circuits: DATA TERMINAL PORTS (Note) STATION TYPECIRCUIT PACKDATA TERMINAL SPECIFICATIONS EIA RS-232 Device ViaData LineRS-232 device must furnish ADU(TN726)signals on ADU pins 2 (TD) and 20 (DTR) and ground on either pin 1 or 7. The ADU furnishes signals on pins 3 (RD) and 8 (CD). The CD signal is also tied to pins 5 (CTS) and 6 (DSR). Some data terminals may require auxiliary power when used with a Z3A1, Z3A2, or Z3A4 ADU (the Z3A5 always requires local power). ADUs require 7 volts on pin 20 (DTR) to operate properly. The following table lists data terminals that have been tested and are known to operate properly without auxiliary power. Note:Refer to Cable Distance Limitations for supported data rates. 5-12
TECHNICAL SPECIFICATIONS Port Specifications (Contd) DATA TERMINALS (Do Not Require Local Power) DATAREQUIRES Z3A1REQUIRES TERMINALor Z3A2 ADUZ3A4 ADU AT&T 4410 X 4415X 510AX ADMs 3A X 31X ADDS Viewpoint * X ConCept HDS 108 X Datamedia Elite 1521 X Hazeltine 1510 X Hewlett Packard 2621A X 2623AX 2640X 2645X 2645AX Teletype BLIT/1 (68000 based) X 5620 (MAC-80 based)X 5420X * Requires Originate/Disconnect Switch. 5-13
TECHNICAL SPECIFICATIONS Port Specifications (Contd) 5-14 VOICE TERMINAL PORTS STATION TYPECIRCUIT PACKSPECIFICATIONS Tip and RingTip Ring Line Single-Line(ZTN78)l 1-Pair Interface (Tip and Ring) Sets (Analog) l Analog signals modulated over DC loop l Loop Voltage: 24 V dc l Signaling: Dual Tone Multifrequency (DTMF) or Dial Pulse l REN (max.): 1.2 l DC Current (max.): 35 mA l Loop Range (24 AWG): 2,000 feet l In-building service only Tip and RingAnalog Line Single-Line(TN742) l 1-Pair Interface (Tip and Ring) Sets(TN746B) (Analog) l Analog signals modulated over DC loop l Loop Voltage: 48 V dc l Signaling: Dual Tone Multifrequency (DTMF) or Dial Pulse l REN (max.): 5.0 l DC Current (max.): 40 mA l Loop Range (24 AWG): 17,500 feet l Supports Out-of-Building, Extended (greater than 2000 feet), Off-Premises, and Bridged Station services (maximum of five bridged stations, and two off-hook simultaneously).
TECHNICAL SPECIFICATIONS Port Specifications (Contd) VOICE TERMINAL PORTS (Contd) STATION TYPECIRCUIT PACKSPECIFICATIONS MET SetsMET Line (Hybrid)(TN735)l 3-Pair Interface 1-Voice pair 2-Control pairs l Analog Voice, Digital Control/Signaling l Power: Phantom Power Over Data Pairs l Bipolar Signaling With 0 V dc Offset l 1 MHz Nominal Signaling Rate l Loop Range: 1000 feet (In-Building service only) MERLIN®ATL Line System Sets(ZTN79) l 3-Pair Interface 7300H Series)(TN762B)1-Voice pair Hybrid)1-Control pair 1-Power pair l Analog Voice, Digital Control/Signaling l Bipolar non-return to zero Iine-coding l 40 kHz Nominal signaling rate l Loop Range: 2000 feet l In-Building and In-Range Out-of-Building (IROB) services only (Local power required when distance is greater than 1000 feet) 5-15
TECHNICAL SPECIFICATIONS Port Specifications (Contd) VOICE TERMINAL PORTS (Contd) STATION TYPE ATL Cordless Telephone CIRCUIT PACK ATL Line (ZTN79) SPECIFICATIONS Handset to Base 1000 feet clear area Base station: l 3-pair Interface 1-Voice pair 1-Control pair 1-Power pair l Analog Voice, Digital Control/Signaling l Bipolar non-return to zero line-coding l 40 kHz Nominal signaling rate l Loop Range: 2000 feet l In-Building and In-Range Out-of-Building (IROB) services only (Local power required when distance is greater than 1000 feet) 5-16
TECHNICAL SPECIFICATIONS Port Specifications (Contd) TRUNK PORTS TRUNK TYPECIRCUIT PACKSPECIFICATIONS Auxiliary TrunkTN763 l Capacity: 4 Circuits l 3-pair Interface: Voice (T, R), Signaling (S, S1), Status (SZ, SZ1) Direct InwardTN753 Dialing (DID) l Capacity: 8 Circuits Trunk l 2-wire (600 Ohm Fixed Impedance) Transmission l Signaling: Wink Start, Delay Dial, or Immediate Dial. Accepts Dial Pulse Signals only l Incoming Service only Tie TrunkTN760B l Capacity: 4 Circuits l Supports Type I E&M, Type I Compatible E&M or Type V Simplex Signaling l 4-Wire Transmission l 3-Pair Interface Transmit Receive Signaling (E&M) l Max Loop Resistance: 650 ohms November 19955-17
TECHNICAL SPECIFICATIONS Port Specifications (Contd) TRUNK PORTS TRUNK TYPECIRCUIT PACKSPECIFICATIONS DS1 InterfaceTN767 l Capacity: 24 Circuits l 4-Wire Transmission l 3-pair Interface: Transmit Receive Loopback Ground StartZTN76 Trunk l Capacity: 8 Circuits l 2-wire (600 Ohms or RC Balance) Transmission l Network Signaling: Ground Start l Two-way or Incoming-only Service Loop StartZTN77 Trunk l Capacity: 8 Circuits l 2-wire (600 Ohms or RC Balance) Transmission l Network Signaling: Loop Start l Two-way or Incoming-only Service 5-18November 1995
TECHNICAL SPECIFICATIONS Recommended Central Office Trunk Facilities The following table provides recommendations for CO trunks based on the number of voice terminals in the system and the calling traffic. CALLING TRAFFIC VOICE TERMINALS 20 25 30 40 50 60 70 80 100 120 140 160 180 200 LIGHT TRAFFIC 3/3 3/4 4/4 4/4 5/4 5/4 5/5 6/5 6/5 7/6 7/6 8/7 8/7 9/8 MEDIUM TRAFFIC 4/4 5/5 6/5 6/6 7/6 8/7 8/7 9/7 10/8 11/9 12/10 13/10 13/11 14/12 HEAVY TRAFFIC 5/5 6/6 8/7 9/8 10/8 11/9 12/10 12/10 14/12 16/13 17/14 19/15 20/16 22/18 Notes: 1. For systems with both one-way and two-way trunks, the first number listed under “Calling Traffic” is the number of two-way trunks required, the second number is the number of one-way trunks required. 2. For systems with just two-way trunks, add the two numbers listed under Calling Traffic to determine the number of trunks required. 5-19
TECHNICAL SPECIFICATIONS Analog Transmission Characteristics Frequency Response: (Station-To-Station or Station-To-CO Trunk, relative toloss at 1 kHz) FREQUENCYLOSS 60 Hz>20 dB 200 Hz