Telephone Cables Selection Guide
Telephone cable types PDV, PDH, HBH and PD-PAP differ by insulation and sheath material, which determines where the cable can be installed; conductor diameter also matters.
This guide explains what to look at when choosing products in the Telephone Cables category.
Telephone cable types
The type name changes with the insulation and sheath material; this in turn determines where the cable can be installed.
- PDV: An indoor cable with polyethylene insulation and a PVC sheath; used in fixed installations inside dry or damp buildings, and in exchange and subscriber distribution.
- PDH: An indoor cable with polyethylene insulation and a halogen-free (HFFR) sheath.
- HBH: An indoor cable in which both the insulation and the sheath are made of halogen-free material.
- PD-PAP: A double-sheathed outdoor cable; used in network lines inside ducts laid underground.
Halogen-free types (PDH and HBH) are chosen in buildings with a high density of occupants to limit smoke density and corrosive gas emission in a fire; manufacturers declare this behavior through flame propagation, smoke density and corrosive gas tests. Being halogen-free does not mean the cable will keep operating during a fire; the distinction is explained in the article is halogen-free cable fire-resistant.
The 0.50 on the product is a diameter, not a cross-section
A cable labeled "30x2x0.50 mm + 0.50 mm" has 30 pairs, that is 60 conductors, and one earth core. The value 0.50 is the diameter of the conductor; the cross-section of a solid conductor with a 0.50 mm diameter is about 0.2 mm². In manufacturer data, the resistance of this conductor is given as at most 97.8 Ω/km and the operating voltage as at most 250 V. These cables are for communication circuits; for supply lines that require cross-section calculation, a power or control cable is used.
In multi-pair cables, the pairs are collected in groups; in 2M HBH cables the pairs are twisted in groups of 10 and each group is identified with a binder tape. When looking for a pair in a distribution box, first follow the group, then the insulation color.
How to choose the number of pairs and the conductor diameter
- Number of pairs: An analog telephone line uses one pair. Spare pairs foreseen in the project are added to the number of lines to be connected. For in-apartment installation, 1- and 2-pair constructions are listed; for floor and building main distribution, 30-, 50- and 100-pair constructions are listed.
- Conductor diameter: As the line gets longer, conductor resistance and signal attenuation increase. In this category, indoor types are listed with 0.50 mm conductors, and outdoor PD-PAP with 0.50 mm and 0.90 mm conductors. In outdoor telephone cables, 0.4 and 0.5 mm conductors are used in short-distance distribution networks and 0.6 and 0.9 mm conductors in long-distance network lines.
- Sheath: Inside a building, a PVC or halogen-free sheath is determined by the fire requirement of the project. For underground lines outside the building, an outdoor type is chosen instead of an indoor cable.
- Earth core: Products with "+ 0.50" in their name carry an additional earth core; choose this construction if the project calls for this conductor.
Telephone cable, data cable and fire alarm cable
A telephone cable is defined for voice-frequency lines. For a computer network (Ethernet), a data cable with a declared category performance is required; these are in the CAT6 cables and CAT6a cables categories. The cable type for fire detection and alarm lines is determined by the project and the relevant regulation; these products are in the fire alarm cables category. For door entry systems see intercom cables, and for the end of the line at the wall see the data and telephone sockets pages.
Brands in this category
- Birtaş Kablo: PDV and HBH indoor cables and PD-PAP outdoor cables with 0.50 mm and 0.90 mm conductors; constructions such as 1, 3, 4 and 15 pairs.
- 2M Kablo: halogen-free HBH cables with an earth core and gray sheath; constructions such as 6, 30, 50 and 100 pairs.
- Reçber Kablo: 2-pair PDV and 30-, 50- and 100-pair halogen-free PDH cables.
- Mekas Kablo: indoor-installation type 1- and 2-pair PDV cables.
Order notes
Products are sold by the meter. Most of the products are listed as made-to-order; for these products the lead time is confirmed before ordering. Each pair count of the same type is a separate product; the type and construction are written together in the product name (like Birtaş PDV 4x2x0.50 mm).
Comparison and selection table
| Selection Criterion | Indoor Telephone & Intercom Cable (PDV / J-Y(St)Y) | Halogen-Free (JH(St)H) Telecom & Alarm Cable | Outdoor / Underground Jelly-Filled Telephone Cable |
|---|---|---|---|
| Conductor & Pairing | 0.50 mm or 0.80 mm solid copper twisted pairs (2×2 to 100×2) | 0.50 mm / 0.80 mm solid copper + LSZH low-smoke zero-halogen jacket | Solid copper pairs + water-blocking petroleum jelly + black PE jacket |
| Screening | Overall aluminum-laminated foil screen (St) + drain wire | Foil screen (St) prevents crosstalk and power-line hum | Moisture barrier & UV/rodent resistant outer sheath |
| Common Pair Counts | 1-pair, 2-pair, 3, 4, 6, 10, 20, 30, 50, 100 pairs | 1×2×0.80, 2×2×0.80 (fire alarm loops) & multi-pair risers | 2-pair to 100+ pairs for campus & underground ducts |
| Typical Application | PBX telephone extensions, intercoms, xDSL & building automation | Public buildings, hospitals, malls & fire detection panels | Underground telecom manholes, outdoor conduits & aerial drops |
Frequently asked questions
What is the difference between PDV and HBH telephone cable?
PDV cable has polyethylene insulation and a PVC sheath. In HBH cable, both the insulation and the sheath are made of halogen-free (HFFR) material; smoke density and corrosive gas emission in a fire are limited. Both are indoor fixed-installation cables and are manufactured in the same pair constructions. The fire requirement of the project determines which one will be used; in buildings with a high density of occupants, halogen-free cable is generally required.
Is the 0.50 value on a telephone cable a cross-section?
No, it is the conductor diameter in millimeters. The cross-section of a solid copper conductor with a 0.50 mm diameter is about 0.2 mm². For this reason, a telephone cable labeled 0.50 does not carry the same current or give the same voltage drop as a signal or control cable with a 0.50 mm² cross-section. In manufacturer data, the resistance of this conductor is stated as at most 97.8 Ω/km.
Can telephone cable be used for the internet?
A DSL connection arriving over the telephone line is carried on the telephone pair as far as the modem. The Ethernet lines running from the modem to computers and network devices, however, require a data cable with a declared category performance (such as CAT5e or CAT6). Because the PDV, PDH and HBH types are defined for voice-frequency lines, they cannot replace a data cable in local network cabling.
How many pairs should the telephone cable have?
An analog telephone line uses one pair. Inside an apartment, a 1- or 2-pair cable is mostly used; the second pair is for a spare or a second line. On main lines between the exchange and the floor distribution boxes, the pair count is found by adding the spare foreseen in the project to the number of lines to be fed from that box, and rounding up to the nearest manufactured construction such as 30, 50 or 100 pairs.
Can an indoor telephone cable be used outside the building?
The PDV, PDH and HBH types are defined by their manufacturers for fixed installation inside buildings. Outdoor types are manufactured for network lines outside the building; with its double-sheathed construction, PD-PAP is used inside ducts laid underground. If part of the line passes outside the building, choose an outdoor type for that part and arrange the transition point according to the project.