Corded ISDN Phones
Corded ISDN phones (S0 desk phones) use the digital ISDN BRI connection (S0 bus, 2B+D) and offer significantly more functions than analogue devices: CLIP (caller ID), CLIR, MSN assignment for multiple numbers, digital voice quality and faster connection setup times. System phones for ISDN PBX systems (e.g. Auerswald COMfort 1200 ISDN) additionally offer PBX functions such as direct call, secretary-boss and call log. With advancing all-IP migration, ISDN phones are becoming rarer; remaining stock and used devices are available. For new installations, we recommend going directly to SIP IP phones.
Common Manufacturers: Auerswald • Agfeo • Siemens • Tiptel • Elmeg
Top sellers in ISDN
ISDN from Agfeo
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 Agfeo 6101545 SENSORfon ST53 black Up0/S0
For ES systems (from version 2.2). Movable and illuminated graphic display (including dark mode), control pad for effective operation, proximity sensor (display, tone call), soft keys, flat design and ...Lieske Part No.: 1597896 Mfg Part No: 6101545 Type: ST 53 SENSORfon schwarz |
345,93 EUR
 ≈ £291.96 | ≈ $387.44
Delivery time from supplier's stock (ca.) 6 workdaysinfo_outline
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Agfeo 6101571 SENSORfon ST53 IP black
For ES (from version 2.2) and HyperVoice systems. Movable and illuminated graphic display (including dark mode), control pad for effective operation, proximity sensor (display, tone call), soft keys, ... Lieske Part No.: 1598064 Mfg Part No: 6101571 Type: ST 53 IP SENSORfon schwarz |
345,93 EUR
≈ £291.96 | ≈ $387.44
Delivery time from supplier's stock (ca.) 5 workdaysinfo_outline
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Agfeo 6101577 Telephone DECT75 IP black
DECT 75 IP The handheld part for workshops and retailers strong | robust | water-resistant jet-proof and dust-proof according to IP 65 protection class works in environments from -10 to +55 degrees ... Lieske Part No.: 1102302 Mfg Part No: 6101577 Type: DECT 75 IP schwarz |
489,51 EUR
≈ £413.15 | ≈ $548.25
Delivery time from supplier's stock (ca.) 6 workdaysinfo_outline
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Agfeo 6101578 Telephone DECT77 IP white
DECT 77 IP Particularly robust not only for healthcare and medical use | water resistant | antibacterial antibacterial in accordance with ISO 22196 (2nd Edition) high-quality, luminous membrane ... Lieske Part No.: 1102301 Mfg Part No: 6101578 Type: DECT 77 IP weiß |
489,51 EUR
≈ £413.15 | ≈ $548.25
Delivery time from supplier's stock (ca.) 5 workdaysinfo_outline
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Agfeo 6101650 Telephone DECT78 IP anthracite
DECT handheld device for the AGFEO DECT IP base! Housing rubber coating, dustproof, shockproof and waterproof according to protection class IP65, suitable for antibacterial use according to ISO 22196 ... Lieske Part No.: 1593682 Mfg Part No: 6101650 Type: DECT 78 IP |
489,51 EUR
≈ £413.15 | ≈ $548.25
Delivery time from supplier's stock (ca.) 6 workdaysinfo_outline
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Agfeo 6101728 SENSORfon ST54 IP black
ST 54 IP - Telephoning with SENSORfon function With the new SENSORfon ST 54 IP we are responding to the wishes of our specialist retailers! A highlight of the new ST 54 IP business office telephone ... Lieske Part No.: 1373258 Mfg Part No: 6101728 Type: ST 54 IP SENSORfon schwarz |
418,28 EUR
≈ £353.03 | ≈ $468.47
Delivery time from supplier's stock (ca.) 5 workdaysinfo_outline
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Agfeo 6101729 SENSORfon ST54 IP silver
ST 54 IP - Telephoning with SENSORfon function With the new SENSORfon ST 54 IP we are responding to the wishes of our specialist retailers! A highlight of the new ST 54 IP business office telephone ... Lieske Part No.: 1373261 Mfg Part No: 6101729 Type: ST 54 IP SENSORfon silber |
418,28 EUR
≈ £353.03 | ≈ $468.47
Delivery time from supplier's stock (ca.) 6 workdaysinfo_outline
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ISDN from Auerswald
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 Auerswald 90242 COMfortel M-720 titan DECT handsets IP20 Li-Ion battery
The COMfortel M-720 not only impresses with its elegant appearance and slim design, but also with its high performance. Because the handpiece is equipped with first-class business functions such as ...Lieske Part No.: 1956029 Mfg Part No: 90242 |
151,71 EUR 158,10 EUR
≈ £128.04 | ≈ $169.92
Made to order · Delivery time approx. 20 workdaysinfo_outline
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Auerswald 90262 COMfortel D-400 SIP telephone with expansion option
. Intuitive user interface . Brilliant and high-resolution 4.3' display . 20 self-labeling function keys including LED signaling . USB port for additional key extensions . Up to 3 key extensions per ... Lieske Part No.: 1592751 Mfg Part No: 90262 Type: COMfortel D-400 |
287,17 EUR 290,18 EUR
≈ £242.37 | ≈ $321.63
Made to order · Delivery time approx. 20 workdaysinfo_outline
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Auerswald 90263 COMfortel D-600 SIP-telephone corded
COMfortel D-600 Lieske Part No.: 1056758 Mfg Part No: 90263 |
517,39 EUR 522,84 EUR
≈ £436.68 | ≈ $579.48
Made to order · Delivery time approx. 20 workdaysinfo_outline
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ISDN from Tiptel
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 Tiptel 1020040 Retell Ergophone 24
24 lettered keys for direct calls-20 possible single-digit numbers between the phone socket and connect existing analog telephone-suited for cordless DECT phones-No external power supply or batteries ...Lieske Part No.: 358225 Mfg Part No: 1020040 |
31,85 EUR 31,89 EUR
≈ £26.88 | ≈ $35.67
Made to order · Delivery time approx. 20 workdaysinfo_outline
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Tiptel Ergo Phone 1200
Ring memory, messages must not be deleted werden- An announcement, 20 records 40 minutes Aufnahmekapazität- flash memory without batteries (data retention) - 4 buttons for Hauptfunktionen- 5 hidden ... Lieske Part No.: 154394 Mfg Part No: 1081200 |
39,83 EUR 39,88 EUR
≈ £33.62 | ≈ $44.61
Made to order · Delivery time approx. 20 workdaysinfo_outline
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ISDN from Yealink
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 Yealink wall mount for EXP40
Lieske Part No.: 1570205 Mfg Part No: WMB-EXP40 |
13,84 EUR
≈ £11.68 | ≈ $15.50
Made to order · Delivery time approx. 20 workdaysinfo_outline
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Corded ISDN Phones – Product Details & Advice
Corded ISDN phones (S0 desk phones) use the digital ISDN BRI connection (S0 bus, 2B+D) and offer significantly more functions than analogue devices: CLIP (caller ID), CLIR, MSN assignment for multiple numbers, digital voice quality and faster connection setup times. System phones for ISDN PBX systems (e.g. Auerswald COMfort 1200 ISDN) additionally offer PBX functions such as direct call, secretary-boss and call log. With advancing all-IP migration, ISDN phones are becoming rarer; remaining stock and used devices are available. For new installations, we recommend going directly to SIP IP phones.
Analogue alternatives: Analogue Phones. IP system phones: IP System Phones.
Frequently Asked Questions
▶ Do ISDN phones still work after the all-IP migration? No – not directly. ISDN phones require an S0 bus connection. After all-IP conversion, the physical ISDN exchange line is discontinued. Via an IP PBX with integrated S0 port or an ISDN-to-SIP gateway, ISDN phones can continue to operate. Recommendation: switch to SIP phones long-term. |
▶ What is MSN in ISDN? MSN (Multiple Subscriber Number) refers to the multiple numbers that can be assigned to an ISDN BRI connection (typically 3–10 MSNs). Each ISDN terminal responds only to its assigned MSN – so phone, fax and modem can have different numbers on a shared connection. |
▶ Can I call and send fax simultaneously via ISDN? Yes – ISDN BRI has 2 independent B-channels (64 kBit/s each). One can be used for calling while the other transmits a fax. Prerequisite: terminals are correctly configured (MSN assignment, no EKTS conflict). When all 2 B-channels are in use, no further connections are possible. |
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