description the XE0020 and XE0020c are complete compact telephone interface modules. as with all xecom daas the XE0020 and XE0020c include ring detection, switch-hook, and loop current holding circuits. in addition both the XE0020 and XE0020c include two line monitors to insure unobtrusive customer premises operation. the XE0020c also passes the caller id signal through to the system host. xecom designed the XE0020 and XE0020c for unobtrusive operation in residential applications. two integral line monitors prevent interference with the residents calls. connect detect verifies line availability before the equipment seizes the line. this will prevent the equipment from interrupting a residents call. handset interrupt signals the system host to drop the call in progress when the resident picks- up an extension phone. this feature permits the resident to interrupt the call in case of emergency. caller id permits the host to identify incoming calls and answer only those from designated call centers. together these features give residents priority use of the telephone line without shutting out the equipment. xecom XE0020 telephone line interface with active line monitoring XE0020 and XE0020c 8/97 features * small size: 2.0" by 0.5" by 0.4" thick; * supports data transfer at 33,600 bps; * fcc part 68 compliant; * ring detection; * continuous connect detect monitor; * handset interrupt monitor * single +5 volt power supply; * hookswitch control * caller id signal path (XE0020c) models XE0020: includes ring detect , hookswitch, handset interrupt, connect detect, telephone line transformer, loop current holding circuit; XE0020c: XE0020 features plus caller id signal pass through; block diagram oh ri ring tip t1 t2 line transformer hook- switch ring detect cd line voltage monitor loop current holding circuit hint caller id (optional)
1 ring ring is one of two signals which form the telephone network connection (rj11 pin 4). the XE0020 is not sensitive to the polarity of the battery voltage on the telephone line. ring has 1500 volts isolation from the rest of the circuitry which must be preserved throughout the system. 2 tip tip provides the second connection to the telephone network (rj11 pin 3). tip has 1500 volts isolation from the rest of the circuitry. this isolation must be preserved throughout the system. 3 oh hook-switch relay control an active high input. a high on oh closes the internal relay and connects the equipment to the telephone line. 4 t1 t1 connects directly to the secondary side of the XE0020's internal telephone line transformer. 5 gnd this signal is used as common reference for all of the control signals in the XE0020. signals on t1 and t2 are not referenced to ground. xecom (2) XE0020 mechanical specifications a b c d e f g h i j d e e a - 0.400 - 10.16 b - 0.520 - 13.21 c - 2.020 - 51.05 d 0.040 0.060 1.02 1.52 e 0.090 0.110 2.29 2.79 f 0.790 0.810 20.07 20.57 g 0.490 0.510 12.45 12.95 h 0.390 0.410 9.91 10.41 i 0.040 0.060 1.02 1.52 j 0.125 0.200 3.18 5.08 inches millimeters dim min max min max pin size: 0.025" by 0.025" recommended hole size: 0.056" all pins tin-plated. 12 345678 910 oo oooooo o o ring tip oh t1 gnd vcc t2 /ri hint /cd XE0020/XE0020c pin configuration & descriptions bottom view pin name description
recommended parts designation description c1 .01 microfarad c2,c3 47 pico farad, 3000 volts z1, z2 zener diode, 4.3 volts fb1, fb2 ferrite beads (tdk part number ccb30-453215b) mov1 minimum breakover 220 volts (teccor electronics part number p2600ba70) xecom (3) XE0020 pin name description pin descriptions continued 6 vcc vcc provides the + 5 volt power source for the XE0020. 7 t2 t2 connects directly to the secondary side of the XE0020"s internal telephone line transformer. 8 /ri ring indicate, output, active low, ttl, ri provides a ring frequency pulse train representation. an external 56k pull-up resistor is required to correctly bias the ring indicate output. 9 hint handset interrupt is an active high output from the modem. hint goes high for one second if an extension telephone is picked-up while the daa has control of the line. when the host sees hint go high, it should immediately lower oh to disconnect the XE0020 or XE0020c from the telephone line. 10 /cd connect detect, output, active low, ttl. /cd indicates that the XE0020 is connected to the telephone line and the telephone line is not in use. XE0020/XE0020c typical connection diagram rj11 c2 c3 fb1 fb2 mov1 modem data pump ring tip +5 volts vcc /ri t1 t2 oh ring rxa txa1 txa2 off hook hint /cd controller c1 z1 z2 56k 340 ohms gnd 4 3 15 ohms 1/2 w 15 ohms 1/2 w
xecom (4) XE0020 electrical specification (vcc=+3v ?0%, ta=0 to 70 deg c) power supply current off hook, 5.0 volts 10 15 ma transmit insertion loss 600 ohm impedance, 1000 hz 1.7 2.7 3.7 db receive insertion loss 600 ohm impedance, 1000 hz 1.7 2.7 3.7 db line impedance at 1000 hz, rm 340 ohms 540 600 660 ohms coupler match input impedance to t1 & t2 330 340 350 ohms input impedance ring detect min. ac voltage between tip & 38 150 vrms sensitivity (on-hook) ring type b ringer ring detect ringing voltage of 40 vrms 100 ua peak current applied between tip & ring ring detect no ringing voltage present 10 ua idle current ring indicate output ring voltage present on tip 0.2 0.5 volts voltage & ring loop current switch on: (off-hook) 2.0 3.0 volts control voltage off: (on-hook) 0.2 0.5 volts loop current switch 15 25 ma control current loop current off-hook current draw from 20 100 ma telephone line total harmonic at 1800 hz, -9 dbm signal level -72 -76 dbm distortion connect detect 15 volts threshold handset interrupt 40 milliamps loop current 0.5 1.0 1.5 volts battery voltage change at tip and ring parameter conditions min typ max units absolute maximum ratings storage temperature -25 o c to +85 o c operating temperature range 0 o c to +70 o c maximum lead temperature (soldering 2 seconds per wave) 260 o c
xecom (5) XE0020 telephone line connection information when developing a product to be connected to the telephone line, it is necessary to use a circuit described as a data access arrangement (daa) which is approved by the appropriate governmental agency. in the us, for example, this agency is the federal communications commission (fcc), while in canada it is industry canada. these agencies test and approve the product to ensure that it meets their specifications, thereby protecting the telephone system from damage and protecting the user from high voltage transients (such as lightning strikes) which may come down the telephone line. the XE0020 has been designed to meet fcc part 68 requirements for hazardous voltage, surge protection and leakage current. if the system transmits data, or dtmf tones on the telephone line, the user must certify that these transmitted signals meet fcc requirements for maximum transmission levels of out of band energy and billing delay. full details may be obtained from the fcc under part 68 of the fcc rules and regulations, or in title 47 of the code of federal regulations, however the basic requirements are as follows: 1. maximum transmit level for the normal ?ermissive?(standard) telephone line, equipment which transmits data (such as a modem) must not exceed a transmission level of -9 dbm. 2. out of band energy data equipment must not transmit ?ut of band?energy on the telephone line which exceeds the following limits: frequency range max. power 200hz to 3990hz -9 dbm 3990hz to 4005hz -27 dbm 4005hz to 16khz -16 dbm 8khz to 94khz -47 dbm 86khz to 270khz -46 dbm 270khz to 6mhz -6 dbm 3. dtmf transmission level if the system is capable of dtmf dialing, the maximum dtmf transmission level must be less than 0 dbm averaged over a 3 second interval. 4. billing delay a delay of 2 seconds or greater is required after the time the XE0020 is taken ?ff hook?and before any information is transmitted. this is required to ensure that billing information may be exchanged between telephone company central offices without interference. the user of the XE0020 must certify to the fcc that the final system meets the requirements of part 68 which include the criteria above as well as the high voltage isolation provided by the XE0020. this is generally accomplished through an independent testing lab which test the system and submits the proper paperwork to the fcc for approval. since the XE0020 already complies with fcc part 68 rules, this is a relatively simple proces s.
xecom (6) XE0020 copyright, xecom 1997 while xecom, inc. has made every effort to ensure that the information presented here is accurate, xecom will not be liable for any damages arising from errors or omission of fact. xecom reserves the right to modify specifications and/or prices without notice. product mentioned herein are used for identification purposes only and may be trademarks and/or registered trademarks of their respective companies. xecom incorporated 374 turquoise street, milpitas, ca 95035 web site www.xecom.com ph:408 -945 -66 40 fax: 408 - 942-1346 e-mail info@xecom.com terms of sale devices sold by xecom are covered by the warranty provisions appearing in its terms of sale only. xecom makes no warranty, express, statutory, implied, or by description regarding the information set forth herein, or regarding the freedom of the described devices from patent infringement. xecom makes no warranty of merchantability or fitness for any purposes. xecom reserves the right to discontinue production and change specifications and prices at any time and without notice. this product is intended for use in normal commercial applications. applications requiring extended temperature range, unusual environmental requirements, or high reliability applications, such as military, medical life-support or life-sustaining equipment, are specifically not recommended without additional processing and authorization by xecom for such application. xecom assumes no responsibility for the use of any circuitry other than circuitry embodied in a xecom product. no other circuits, patents, or licenses are implied. life support policy xecom's products are not authorized for use as critical components in life support devices or systems. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions provided in the labeling, can be reasonably expected to result in significant injury to the user. a critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause failure of the life support device or system, or to affect its safety or effectiveness.
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