Comparison of Testing Requirements

Comparison of Type 1 testing requirements from 
Telcordia and TIA/EIA

Relevant Standards

There are currently two standards which are used as a guideline to producing a robust Type 1 Caller ID device. The first standard that was introduced is from Telcordia, formally called Bellcore. While they produce a number of standards on the subject of telephony, they published one document in particular, which is useful as a testing guideline. This document called SR-3004, "Testing Guidelines for Analog Type 1, 2, and 3 CPE as Described in SR-INS-002726", brought together the requirements from a number of other Telcordia standards to produce a test suite for evaluating a Type 1 Caller ID device. The version of the standard used in the creation of this comparison is Issue 2, January 1995. It is expected that Telcordia will release a revision to this document in the near future and may be as earlier as the end of 2000. While SR-3004 also addresses the requirements for a Type 2 and Type 3 CPE, requirements these are outside the scope of this article.

The other standards body that publishes standards on Caller ID is TIA/EIA. This group is formed from industry participants who meet on a regular basis to determine basic requirements for telecommunication and other electronic equipment. In the case of Caller ID they currently publish a document called TIA/EIA-716 "Telecommunications Telephone Terminal Equipment Type 1 Caller Identity Equipment Performance Requirements". The current issue for this document is November 1998. TIA/EIA-716 is the first in a series of three documents to be created by TIA and only covers the requirements for a Type I device. The Type II requirements are in a separate document called TIA/EIA-777 and TIA will soon publish a third document, incorporating the requirements for Type 1, 2 and 2.5 in a single source.

TIA/EIA-716 vs. SR-3004

This article breaks down the Caller ID device requirements into areas. These being the physical layer and the data layer

The physical layer is defined as the physical properties that control the transmission of the FSK to the device. These would include any parameters that can be expressed as a time, a frequency or an electrical level.

The data layer is defined as the binary data that is sent between the central office and the receiving device. The data would include the message type, parameter words, checksum and also the channel seizure and mark signals preceding the data.

The following tables show the requirements in a point form and indicate the document section the specification is from.

Physical Layer Requirements

The following table is a quick reference between the physical layer requirements of TIA/EIA-716 and the requirements of SR-3004.

 

TIA/EIA-716

Telcordia (Bellcore) SR-3004

Parameter

Section

Requirement

Section

Requirement

Mark Frequency

4.4.1

1%

3.1.1
3.1.11

1%
( 100 Hz) 3

Space Frequency

4.4.1

1%

3.1.1
3.1.11

1%
( 100Hz) 3

Baud Rate

4.4.4

1%

3.1.1
3.1.11

1%
(1150 to 1250) 3

Mark Level

4.4.2

19 mV to 476mV1

3.1.2
3.1.11

-12 to -32 dBm2
(-12 to > 40 dBm) 3

Space Level

4.4.2

12 mV to 476mV1

3.1.2
3.1.11

-12 to -36 dBm2
(-12 to > 40 dBm) 3

Reject Level

4.4.2

3 mV1

3.1.11

(-50 dBm)3

Twist

4.4.3

+10 dB / -6 dB

3.1.3

10 dB

Ringing On time

4.3.1

Meets T1.401

3.1.4

Duration 200mS

Ringing Off time

4.3.1

Meets T1.401

3.1.4

2.0 to 6.0 Seconds

Interfering Noise

4.4.5

-18 dB 60 f
-12 dB 60 f 120 Hz
-6 dB 120 f 200 Hz
+25 dB 200 f 3200 Hz
+6 dB f 3200 Hz

3.1.5

-20 dB 200 f

+25 dB 200 f 3200 Hz

-20 dB f 3200 Hz

Echo Noise

4.4.6

Delay 1 to 3 ms
Atten. 13 dB and 26 dB

n/a

Not Specified

Channel Seizure Dropout

4.5.3

10 ms

3.1.10

10 ms

Mark Signal Dropout

4.5.3

Not Specified

3.1.10

10 ms

Markout

4.6.8

0 to 4400 ms

n/a

Not Specified

Channel Seizure delay

4.3.1

250 ms to 3600 ms

3.1.8
3.1.11

250 ms to 3600 ms
(100 ms to 3600 ms) 3

Delay to Ringing after Data

4.3.1

200 ms

n/a

Not Specified

Immunity to False Ringing

4.3.1

Display should not change

3.1.6

Display should not change

Reception after power ringing

n/a

Not Specified

3.1.7

After 2 to 20 Rings

1 Specified from a 900 ohm source, and measured in an open circuit termination
2 Specified from a 900 ohm source, and measured in a 600 ohm termination
3 Indicates an extended operating condition. The extended operating conditions cover a wider set of requirements not all of which are not shown in the table above.

 

Data Layer Requirements

The following table is a quick reference between the data layer requirements of TIA/EIA-716 and the requirements of SR-3004.

 

TIA/EIA-716

Telcordia (Bellcore) SR-3004

 

Section

Requirement

Section

Requirement

Channel Seizure

4.5.1

70 to 320 Bits

3.2.1

280 to 320 Bits
(200 to 350 Bits)3

Mark Signal

4.5.2

40 to 525 Bits

3.2.1

160 to 200 Bits
(70 to 210 Bits)3

Stuffed Mark Bits

4.6.6

0 - 100 bits / packet
500 bits / message max

3.2.5

0 to 25 Bits between message words

Message Type Verification

4.6.2

Ignore when invalid

3.2.2

Ignore or display error when invalid

Message Length errors

n/a

Not Specified

3.2.3

Ignore or display error when invalid

Checksum Error

4.8.1

Ignore or display error

3.2.4

Ignore or display error when invalid

Parameter Type Verification

4.6.4

Ignore when invalid

n/a

Not Specified

Parameter Length errors

n/a

Not Specified

3.2.6

Ignore or display error when invalid

Space Bits after Checksum

4.6.8

Ignore

n/a

Not Specified

SDMF VMWI

4.7.5.1

Valid data should correctly set the indicator

3.2.6

Valid data should correctly set the indicator

MDMF VMWI

4.7.5.2

Valid data should correctly set the indicator

3.2.6

Valid data should correctly set the indicator

Out of Range data

4.8.3

Display, ignore or correct

n/a

Not Specified

3 Indicates an extended operating condition. The extended operating conditions cover a wider set of requirements not all of which are not shown in the table above.

 

Summary

The two tables above show that, in some cases, it is the TIA standard that has the more stringent requirement and in other cases it is the older SR-3004. In a robust design it may be possible to meet the requirements of both standards in a single implementation. This provides the best performance in the field since many of the requirements have come directly from field experience within North America.

The next article in the series will compare the requirements for a Type 2 Caller ID device.