TS 04.91 – Call Transfer Supplementary Services Procedures
3GPP TS 04.91 is the 3GPP Technical Specification for Call Transfer Supplementary Services Procedures. It is published in 3 releases (R96 to R98); the latest version is 7.0.1 in R98.
Defines radio interface procedures for Explicit Call Transfer (ECT) supplementary service in GSM networks, enabling subscribers to connect two existing calls.
Releases and versions of TS 04.91
| Release | Latest version | Links |
|---|---|---|
| R98 | 7.0.1 | Read · Download (3GPP) |
| R97 | 6.0.1 | Read · Download (3GPP) |
| R96 | 5.1.2 | Read · Download (3GPP) |
Scope of TS 04.91
Category: Services (Supplementary Services). Technology generation: 2G. Network layer: Services.
Who should read this specification?
- Network operators
- Device manufacturers
- Regulators and standards bodies
- Researchers and academics
Implementation notes
Complexity level: Intermediate. Implementation difficulty: Medium.
Key technologies
Other specifications in the 04 series
- TS 04.86 Charging Supplementary Services Procedures
- TS 04.87 User-to-User Signalling Stage 3 Specification
- TS 04.88 Call Barring Supplementary Services Procedures
- TS 04.90 USSD Operations Stage 3 Specification
- TS 04.93 CCBS Stage 3 Procedures Specification
- TS 04.96 CNAP Procedures for Name Identification Services
Related glossary terms
Related topics
Frequently asked questions
What is 3GPP TS 04.91?
3GPP TS 04.91 is the 3GPP Technical Specification for Call Transfer Supplementary Services Procedures. Defines radio interface procedures for Explicit Call Transfer (ECT) supplementary service in GSM networks, enabling subscribers to connect two existing calls.
Which 3GPP releases include TS 04.91?
TS 04.91 is published in 3 releases, from R96 to R98. The latest version on 3GPP Explorer is 7.0.1 (R98).
What category does TS 04.91 belong to?
TS 04.91 belongs to the Services (Supplementary Services) category of 3GPP specifications. It applies to 2G networks.
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