How does an analogue line work?
An analogue line operates by converting sound into variable electrical voltage. The speaker's voice vibrates the microphone diaphragm, which transforms mechanical vibration into an electrical signal. This travels along a copper cable pair to the other party, where it is converted back into sound in the receiver.
Compared to digital technologies such as ISDN (Integrated Services Digital Network) or VoIP (Voice over IP), this is a simple technology without compression or encoding. The advantage is zero dependence on local device power: the telephone receives energy directly from the line supplied by the operator's exchange.
The technical limitations of analogue lines are well known: they carry only one call per pair of cables, bandwidth is limited and signal quality degrades with cable length.
Where do analogue lines still exist in companies?
Although VoIP and digital connections have gradually displaced analogue lines, they can still be found in certain situations:
- As a backup for alarms, lift call buttons or payment terminals, devices that require a simple telephone connection without reliance on the internet.
- In buildings with older cabling where reconstructing the structured network is not economically viable.
- For smaller businesses in areas without available DSL or fibre optic connections.
- Like a fax line, where older equipment for IP conversion operates unreliably.
An analogue line requires an analogue telephone or an ATA (analogue telephone adapter) if you wish to connect it to a modern PBX (private branch exchange) or VoIP system.
Analogue line and transition to Virtuální ústředna
When switching to cloud telephony, analogue lines are typically discontinued and replaced by SIP trunk channels via an internet connection. However, if you have analogue telephones or special devices (alarm system, intercom), they can be connected to the virtual PBX using an ATA adapter.
On virtualni-ustredna.cz you can switch from analogue lines to VoIP without needing to purchase a physical PBX, all that is required is an internet connection and compatible equipment.
Frequently Asked Questions
Can an analogue telephone be connected to a virtual PBX?
Yes, using an ATA adapter (analog telephone adapter), an existing analogue device can be connected to a VoIP system. The adapter converts the analogue signal into the digital SIP protocol, which is then processed by the Virtuální ústředna.
What is the difference between an analogue line and ISDN?
ISDN (Integrated Services Digital Network) transmits voice in digital form and enables multiple calls over a single connection. An analogue line is an older technology that transmits voice as a continuous electrical signal and supports only one call per pair of cables.
Why were operators of the analogue line being cancelled?
Analogue infrastructure is costly to maintain and capacity-limited. Operators are gradually switching to IP networks, which are more flexible, better scalable and cheaper to operate.