Colt launches Voice Line (v)

Colt Voice Line (v) is a Colt product that delivers classic ISDN functionality over SIP trunking. Companies receive an ISDN service that already runs on a SIP trunk basis, together with a SIP-enabled connection over the Colt IP network. This makes the next migration step towards modern IP-based voice services easier, without forcing companies to replace their entire phone system infrastructure at once. Colt positions the product as a bridge between the ISDN switch-off and a full SIP trunk migration for mid-sized and larger companies.

With Colt Voice Line (v), companies first receive an ISDN service delivered via SIP trunking. A SIP-enabled connection over the Colt IP network then becomes available, preparing the switch to a full IP-based phone system. This allows the migration to be planned in stages instead of changing numbers, devices and phone system all at once. Access options such as wDSL, ULL or 3rd party Ethernet allow a connection tailored to the site throughout the transition.

Colt Voice Line (v) offers availability of at least 99.9 percent over a redundant, fail-safe fiber optic network, plus SLAs for stable voice quality. It also includes simple number portability, flexible upgrade and downgrade options, and convenience functions such as call forwarding, hold, blocking and call waiting. An online portal gives companies transparent access to call detail records, invoices and reports, something classic ISDN typically cannot offer in this form.

Access to Colt Voice Line (v) is possible via wDSL, ULL (unbundled local loop) or 3rd party Ethernet. This allows the service to be adapted to different site conditions, regardless of whether a suitable fiber or copper connection is already in place. According to Colt, upgrades and downgrades of the booked capacity are possible at any time, so companies can flexibly adjust their connection to growing or shrinking requirements without changing provider.

Yes. Colt Voice Line (v) supports porting existing numbers when switching to Colt, so companies can keep their established phone numbers. This significantly reduces the organisational effort of migration, since customers, partners and internal processes do not need to be switched to new numbers. Combined with flexible access options and guaranteed availability of 99.9 percent, the switch can be carried out with minimal disruption to daily business.

The market for voice services has been changing since the ISDN switch-off was announced in 2016: traditional PMX ISDN solutions are gradually being replaced by SIP trunks. Companies that migrate early avoid short-term pressure and can plan the switch in a structured way, for example with a product like Colt Voice Line (v), which already delivers ISDN functionality via SIP trunking. SAVECALL compares providers on a carrier-independent basis to find the solution that fits your existing phone system.